WASHINGTON (AFP) - United States President Barack Obama will send his diplomatic and defence chiefs to Capitol Hill on Tuesday to intensify a fervent White House effort to win support for military strikes in Syria.
Secretary of State John Kerry and Defense Secretary Chuck Hagel will testify before the Senate Foreign Relations Committee in what will be one of the most high-profile political set pieces in Washington in weeks.
Mr Kerry, who used to run the committee and Mr Hagel, a Republican who emerged as a fierce critic of former president George W. Bush's Iraq policy, are both former senators.
The administration faces a tough task in winning support for military action in Syria to punish a chemical weapons attack nearly two weeks ago, after Mr Obama shocked the world on Saturday by announcing he would seek authorisation for military action from Congress.
Of the two chambers of Congress, the Senate is seen as the easier sell, as it is run by Mr Obama's Democrats and contains a number of Republicans who have been pressing for military action.
The Republican-run House of Representatives however includes many conservatives who have blocked Mr Obama's agenda across the board, and may be keen to thwart the President abroad, despite his warnings that US credibility is at stake, as it has already done at home.
Most of official Washington was on hiatus on Monday for the annual Labour Day holiday, but Mr Obama was meeting two of his most hawkish foreign policy critics, Republican Senators John McCain and Lindsey Graham.
Both men have repeatedly called on Mr Obama to drop his reluctance to arming the opposition in Syria and to embrace more robust military action than the "limited" and "narrow" action the President envisages in Syria.
But both senators have reputations as mavericks and are sometimes pragmatic dealmakers across the political aisle, so their support for a strike would be a tangible victory for Mr Obama as he tries to win over Congress.
The Senate hearing on Tuesday will take place ahead of the scheduled return to work of Congress on Sept 9 There are no plans currently, however, for the House to be recalled before then.
Mr Obama has a limited window this week for personal politicking on Syria, as he is due to leave town on Tuesday evening to visit Sweden and to go to the Group of 20 summit in Russia.
Mr Obama made calls over the weekend to individual members of Congress, as did Vice-President Joe Biden.
A senior White House official said the administration would deploy all of its possible resources on Capitol Hill and beyond to sway opinion on Syria vote.