Adopting a fast-paced strategy, the United States is gathering support for a UN Security Council resolution demanding Syria's cooperation in an investigation into the assassination of former Lebanese Prime Minister Rafik Hariri. The target date for Secretary of State Condoleezza Rice and foreign ministers to agree on a resolution is next Monday in New York. US ambassador John R. Bolton and other Security Council ambassadors are due to meet on Tuesday. Punitive economic measures have not been ruled out. The Bush administration was quickly backed by Britain, its closest partner. Foreign Secretary Jack Straw accompanied Rice last weekend on a homecoming trip to Alabama and discussed strategy with her. And Ben Bot, the foreign minister of The Netherlands, lent his support at a meeting Monday with Rice at the State Department.