United States President Barack Obama has renewed sanctions against Syria, saying it supports terrorist groups and is pursuing weapons of mass destruction.
The US has tried to engage with Syria, the BBC reports, but recently accused Damascus of arming the Lebanese militant group Hezbollah with sophisticated missiles.
Syria has dismissed the claims that it is supplying Scud missiles to Hezbollah.
Mr Obama says the Syrian government has made some progress in checking the infiltration of foreign militants into Iraq.
But he says its continuing support for terrorist organisations, and pursuit of weapons of mass destruction and missile programmes, pose an unusual and extraordinary threat to US security.