Up to six people are believed to have been arrested as police conducted a string of raids across Sydney as part of their investigation into the city's gangland warfare.  The co-ordinated raids, which unfolded just after midday on Tuesday, are reportedly connected to the bloody execution of crime figure Pasquale Barbaro, who was shot down on an Earlwood footpath earlier this month.  About half a dozen people were arrested in the raids which took place at 13 properties, the ABC reports, including four at Sydney's Olympic Park.  Witnesses say two men were tackled to the ground when heavily armed officers swarmed the precinct.  "They were just face down on the ground when we went out there," a female employee from nearby business Sports Camps Australia, who wished to remain anonymous, told AAP.  "(The police) had unmarked cars, and they all just kind of came out of nowhere so it looked like they'd obviously been in position waiting for these two guys to come back from wherever they were and pounced on them."  The employee described the arrested pair as Middle Eastern or European in appearance and aged in their 30s.  A white Holden Commodore has also been towed away.  NSW Police have confirmed multiple search warrants were being executed at properties across the city but would not give any more details.  "As the operation is ongoing no further information is available," a police spokesman said.  Seven Network footage showed several police cars and a heavy presence on Herb Elliott Avenue and Showground Road in the Olympic precinct, while other witnesses reported seeing federal police storming an area around the Ibis Hotel just after midday.  Less than two weeks ago, NSW Police Commissioner Andrew Scipione launched Strike Force Osprey after a spate of bloody executions on Sydney's streets of notorious crime figures.  Barbaro, 35, was shot in Earlwood on November 14 and hitman Hamad Assaad, 29, was shot in Georges Hall on October 25.  In April, gangland kingpin and convicted killer Walid Ahmad, 40, was killed in a spray of bullets on the rooftop car park of Bankstown Central shopping centre.  His murder is believed to be in retaliation for the fatal shooting of Safwan Charbaji outside a Condell Park panel beater several weeks earlier.
There are reports of heavily armed officers at Sydney Olympic Park as police confirm they are conducting multiple raids across Sydney.