Lawmakers are heading to the White House on Monday to discuss how to rally support for launching a military strike against Syria.
Rep. Eliot Engel (D-N.Y.), another supporter, is headed there later in the day.
The sessions come as the White House issued a revised list of countries that back using military force against Syria in the wake of last month's chemical weapons attack against civilians. The expanded list includes Albania, Croatia, Denmark, Estonia, Germany, Honduras, Hungary, Kosovo, Latvia, Lithuania, Qatar, Romania and the United Arab Emirates.
Philip Rucker contributed to this report.