US Secretary of State Condoleezza Rice said last night a decision on when the recalled US ambassador to Syria would return may depend on Syria's response.
Ambassador Margaret Scobey was called back to Washington to demonstrate US displeasure with Syria after the assassination of former Prime Minister Rafik al-Hariri of Lebanon, where Syria has 14,000 troops and has long been a power-broker.
The move reflected US unhappiness at Syria's dominance of Lebanon and long-standing US accusations that Damascus has failed to stop people in Syria from supporting the insurgency in Iraq or crack down on Palestinian militants in Syria.
"It's indeterminate at this point," Ms Rice told the Senate Foreign Relations Committee when asked when Ms Scobey, who left Damascus on Wednesday, would go back.
"I think we will have to see how seriously the Syrians take this signal." Before leaving Damascus, Ms Scobey met Syrian Foreign Minister Farouq al-Shara to repeat US concerns about Lebanon, Iraq and anti-Israel militants, a US official said.
When they announced Ms Scobey's recall on Tuesday, US officials said they were considering imposing new sanctions on Syria following the imposition of economic sanctions under the Syrian Accountability Act in May.
Among other sanctions, the United States at the time banned US exports to Syria other than food and medicine, severed banking relations with the Commercial Bank of Syria and barred Syrian flights to and from the United States.