White House spokesman Scott McClellan said on Friday that the Bush administration is moving forward on implementing the Syria Accountability Act.
"We'll have more to say on that very soon," he told reporters.
McClellan said Damascus had not soothed concerns about its "harbouring and supporting of terrorism"; about foreign fighters crossing the Syrian border to take on US-led troops in Iraq; about the Syrian military presence in Lebanon; and about Syria's quest for weapons of mass destruction.
"Those concerns need to be addressed, Syria needs to take them seriously and work to address those concerns, but we are going to continue to move forward on the sanctions," McClellan told reporters.
Syria denies supporting terrorism, though it admits backing legitimate resistance to Israeli occupation of Palestinian territories.
It also denies it is seeking weapons of mass destruction, arguing that the international community should turn its attention to Israel's nuclear stockpile.
In December, US President George Bush signed the Syria Accountability Act, which aims to punish Syria for alleged ties to terrorists, tacit support for resistance fighters in Iraq, and efforts to obtain weapons of mass destruction.
The bill also demands that Syria withdraw the roughly 20,000 troops it has deployed in Lebanon and calls on the governments of Lebanon and Syria to "enter into serious unconditional bilateral negotiations" with Israel in order to secure "a full and permanent peace".
The legislation directs the president to prohibit US exports to Syria of weaponry and so-called "dual-use" technology with both civilian and military applications.
And it directs the president to choose two sanctions from a range that includes restricting US exports and business investment, downgrading US-Syrian diplomatic ties, imposing travel restrictions on Syrian diplomats in the United States, freezing Syria's assets in the United States, and restricting over-flight rights for Syrian aircraft inside US airspace.