EL-BIREH, West Bank — The Palestinian security officers in civilian clothes were nearly indiscernible amid the chaos of young protesters rushing to hurl rocks at Israeli soldiers and scrambling from the gunshots and tear gas they received in return.  One officer chatted with two paramedics. Another watched from his car as young women assembled firebombs. Two others mingled with onlookers sitting on a rocky rise nearby, watching the demonstration below.  Less discreetly, a man inched closer to some protesters to eavesdrop on their conversation. “He’s a snitch,” sniffed a 53-year-old woman, who refused to give her name precisely because she suspected he was an undercover officer.  The relatively low-key presence of Palestinian security forces at protests surging throughout the West Bank this month suggests a shift after years of close coordination with Israeli agencies. With the Palestinian leadership having announced that it will redefine the deeply unpopular security alliance in response to mounting public outrage over it, officers fear the demonstrators could turn the violent uprising aimed at Israel in their direction.  “They are in an impossible situation,” said Andrew Clarno, an assistant professor of sociology at the University of Chicago, who has researched security cooperation, referring to the Palestinian security forces. “They are being squeezed on both sides. They are being told to crack down, and the kids see them as the front line of the occupation.”  Under agreements that began with the Oslo peace accords two decades ago, security coordination between the Palestinian Authority and the Israelis in the West Bank was largely credited with maintaining the calm that has been unraveling in recent weeks, as well as quelling rivals to the Palestinian president, Mahmoud Abbas.  At its peak, the coordination between the two sides was tight and personal, with local officers meeting or calling one another five or more times a day and senior commanders meeting every week or so, said Avi Issacharoff, an Israeli reporter who focuses on Palestinian affairs.  The two sides would share intelligence about suspected militants, and the Palestinians were notified of Israeli arrest raids in West Bank cities ostensibly under full Palestinian control. Palestinian officers regularly assisted Israeli civilians who inadvertently wandered into those cities to return safely to Israeli-controlled territory — 10 times this month alone, an Israeli military official said.  But there were always strains. Palestinians chafed under rules that required Israeli approval of their weapons and ammunition, and the requirement that Palestinian officers and senior officials coordinate with Israeli forces to pass through areas under military control.  Perhaps most visibly, and most jarringly for many Palestinians, their security forces for years tried to block violent demonstrations at Israeli checkpoints or near Israeli settlements.  Nevertheless, the coordination served the interests of both Israel and Mr. Abbas’s Palestinian government, restoring security to lawless areas of the West Bank and suppressing the capacity there of Hamas, the militant movement that is both the biggest threat to Israel and the chief rival to Mr. Abbas’s Fatah Party.  Now, though, that cohesion is rapidly disappearing under the pressure of the uprising. “Politics entered during this last escalation,” said Mr. Issacharoff, who also helped create “Fauda,” a popular TV drama about undercover Israeli intelligence agents. “The Israelis demanded that the P.A. stop the demonstrations, to stop them completely, and the P.A. said no,” he said, referring to the Palestinian Authority.  Raafat Alayan, a senior official of Fatah who is not a member of the Palestinian Authority, echoed the view of many Palestinians. “There is no way to expect the Palestinian Authority security to protect the Israelis while they are killing our people,” he said. “We are unwilling to be Israel’s security guards. If Israel wants security, the solution is political, and not based on military coordination.”  In March, the Palestine Liberation Organization voted to suspend all security coordination with Israel, a step that was seen as largely symbolic. Now, with security coordination under increasing tension, P.L.O. officials say they are studying how to scale back the arrangement or redefine it.  “There is a consensus that the status quo cannot continue,” said one P.L.O. official who spoke on the condition of anonymity because he was not authorized to discuss the matter. But that does not mean the Palestinian Authority can just cancel the agreement outright, he added. “Our security would not survive without coordination. We even have our bullets approved by them,” he said, referring to the Israelis.  The spokesman for the Palestinian government, Ehab Bessaiso, and the spokesman for Israel’s military, Lt. Col. Peter Lerner, declined to discuss the matter, and officials at Israel’s agency for coordination with the Palestinians did not respond to repeated requests for interviews. A retired Israeli security official said the issue was too sensitive for him to comment on.  But several Israeli and Palestinian experts said that coordination had been continuing throughout the crisis, if on a somewhat strained basis. A Palestinian prisoners’ rights group, Addameer, has counted 800 Palestinians arrested by Israeli forces this month, including 500 in the West Bank, in raids most likely aided by coordination.  One hazard for the Palestinians is the threat that Hamas could pose in the West Bank if security cooperation ended. An expansion of Hamas’s presence from Gaza to the West Bank would risk upturning Mr. Abbas’s government. Scaling back coordination would also antagonize international donors who help fund the Palestinian Authority and risk the collapse of the security forces themselves.  “It’s in their interest” to maintain the relationship, said Michael Herzog, a retired Israeli general and a fellow with the Washington Institute for Near East Policy, referring to the Palestinian leadership.  But Palestinian frustrations with security coordination erupted last month after a video emerged showing a group of Palestinian riot police officers beating a 17-year-old boy with clubs as they tried to block demonstrators from reaching an Israeli checkpoint in Bethlehem.  And now, amid the surge of violence in East Jerusalem, the West Bank and scattered Israeli cities, Palestinian forces appear to have recalibrated their approach. The Palestinian Authority does not operate in East Jerusalem, the original locus of the attacks, but the spread of violence to the West Bank over the last week has put security coordination in the spotlight.  The strife continued Sunday in the West Bank, where a Palestinian wounded an Israeli civilian by stabbing him in the chest, the Israeli military said, adding that the attacker was later captured. Elsewhere in the West Bank, an Israeli police officer fatally shot a 17-year-old Palestinian girl who tried to stab him, The Associated Press reported.  Here in El-Bireh and at other frequent flash points, Palestinian forces no longer try to prevent protesters from heading toward Israeli checkpoints and watchtowers. Instead, plainclothes officers just watch for instigators and weapons beyond stones and firebombs.  Uniformed troops take positions on nearby hills, where they can observe developments and spot potential gunmen while remaining unseen by the crowds.  “We are not standing at the D.C.O. checkpoint to spy on our people and write their names down,” said one intelligence officer, referring to the checkpoint on the outskirts of El-Bireh, where protests have raged throughout the month. He spoke on the condition of anonymity, citing government protocol.  He said the forces were under orders to ensure that protesters did not open fire at soldiers, because it would prompt a harsher response.  Even with the scaled-back presence, however, demonstrators remained wary of the security forces’ intentions.  “Those who show their faces get recorded, they take them later from their homes,” Zeid, a 20-year-old student teacher, said while wrapping a sweater around his head to hide his face. Like most demonstrators interviewed, he provided only his first name, fearing he would be arrested later.  “I cover my face from the authority and the army,” Zeid added, referring to the Palestinian government and the Israeli military. “But I’m more afraid of the authority.”  Those suspicions notwithstanding, the Palestinian security forces do appear to have slowed their activities. Musa Abu Dhaim of the Independent Commission for Human Rights, a group that monitors Palestinian rights issues, said it counted 12 arrests in October of suspected Hamas loyalists, a number more typical of a quieter time.  One Hamas activist, a 21-year-old student who also spoke on the condition of anonymity for fear of being seized by Palestinian forces, said October seemed like a stark contrast from September, when he was caught in a detention sweep and interrogated along with 20 of his friends.  “The situation on the street does not allow them to arrest anybody right now,” the student said. “People are too angry, they would turn on the forces.”  As long as the violence continues, many analysts agree, the more the Palestinian security forces will step aside — and the more damage will be done to cooperation efforts with Israel.  “The P.A.’s ability to stop terrorism, to stop Hamas, will be degraded,” Mr. Issacharoff said. “It’s not a day or an hour, it’s a gradual process: In a couple of weeks we might find five people disobeying orders. Then 20, then 125. This is what I am afraid of.”  Jodi Rudoren contributed reporting from Jerusalem.  A version of this article appears in print on October 26, 2015, on page A1 of the New York edition with the headline: Shift in Tactics by Palestinians in Policing Own. Order Reprints| Today's Paper|Subscribe
Amid violent protests in the West Bank, a longtime security alliance with Israel may be redefined in the face of public anger and mistrust.