America has accused Syria of not doing enough to prevent foreign fighters infiltrating through its eastern border into Iraq to attack U.S.-led coalition forces .
US officials accuse regional states , particularly Syria , of not doing enough to prevent foreign fighters from entering Iraq to attack US-led coalition forces .
the seventh layer of the osi model. application layer protocols enable software programs to negotiate formatting, procedural, security, synchronization, and other requirements with the network. - perform application-to-application communication