Washington: US President George W Bush has signed an executive order extending for the fourth time sanctions on Syria for another year.

"I took these actions to deal with the unusual and extraordinary threat to the national security, foreign policy, and economy of the US by the actions of the government of Syria," Bush said in a statement Wednesday.

According to the executive order, properties of certain Syrian officials will be blocked and export of certain goods to the country will be prohibited.

The Bush administration imposed sanctions on Damascus May 11, 2004, then extended them April 25, 2006 and expanded them Feb 13, 2008.

The US has accused Syria of allowing terrorists to use its territory and enter Iraq to fight against the US-led coalition troops.

Syria has denied the charges.