The US is closely watching the Syrian president

The House of Representatives' International Relations Committee voted 33-2 in favour of adding further trade sanctions to those already in force against Syria.

"It has become increasingly clear which side Syria's government has chosen in the war on terror," said House majority leader Tom DeLay.

"Syria's government has obstructed our coalition's work, harboured and funded terrorists, and is even now helping terrorists cross the Syrian border into Iraq to target American soldiers."

Syria, which denies the charges, has little trade with the United States, but the new sanctions could ban US investment there and restrict exports.

Hard line

The sanctions bill is now expected to go before the full House of Representatives next week.

The BBC's Jon Leyne in Washington reports that the White House had initially opposed the legislation - but now that US President George Bush has dropped his objections, it is likely to become law.

Syria hasn't taken any significant action against terrorist groups Richard Boucher, US State Department

Our correspondent says the bill is part of an increasingly hard line being taken by the US administration against Syria.

The move to toughen sanctions comes after Israel's air raid on an alleged Palestinian training camp in Syria at the weekend - a strike which President Bush refused to condemn.

"Syria needs to change course, change its behaviour, stop harbouring terrorists," White House spokesman Scott McClellan told reporters on Wednesday.

Asset freeze

The State Department has also dropped its opposition to imposing new sanctions on Syria.

Department spokesman Richard Boucher said US Secretary of State Colin Powell had made clear during a visit to Damascus in May that legislation would probably follow unless there were significant moves against extremist groups in Syria.

"And that's what we are seeing unfold, because Syria hasn't taken any significant action against terrorist groups," he said.

The legislation, to be known as the Syria Accountability Act, includes a ban on a number of US exports to Syria, specifically weapons and items that can be used in weapons programmes.

Once passed, it would also call on US President George Bush to select two sanctions from a list of six, ranging from freezing Syrian assets in the US to reducing diplomatic and business links.

During the Iraq war, Washington accused Damascus of harbouring fugitives from Saddam Hussein's regime.