President Obama is ratcheting up pressure on lawmakers to support his request for limited U.S. military strikes in Syria. The White House says the Syrian government is responsible for a chemical weapons attack last month near the capital, Damascus.
On Sunday night, the president stopped by a dinner Vice President Joe Biden was holding for Republican senators.
Guests included Lindsey Graham of South Carolina, Susan Collins of Maine, Kelly Ayotte of New Hampshire, Bob Corker of Tennessee, Saxby Chambliss of Georgia and Deb Fischer of Nebraska.
Obama met with the senators for nearly an hour and a half, according to the White House pool report.
Ahead of his prime-time address to the American people on Tuesday, the president and his advisers have scheduled a series of meetings to try to sway lawmakers over to his side on Syria.
Obama has six network interviews scheduled Monday. He plans to meet with Senate Democrats on Tuesday, according to an unidentified official who spoke to The Associated Press.
In Tuesday's speech, Obama will try to convince the public that limited air strikes in Syria are necessary to respond to the alleged use of chemical weapons by the Assad regime.
Before the address, White House officials will also be out defending the president's message on Syria.
National Security Adviser Susan Rice will deliver a speech on Syria to the New America Foundation on Monday. She also is expected to meet with members of the Congressional Black Caucus.
White House Chief of Staff Denis McDonough appeared on five network shows Sunday and is scheduled to meet with the House Democratic Caucus on Tuesday.
On Capitol Hill, classified briefings for members of Congress will be held Monday and Wednesday.
The Senate is scheduled to begin voting on a Syria resolution Wednesday, and a final vote may come at the end of the week. The House is expected to vote next week.
A survey by The Associated Press finds that House members who have staked out positions are either opposed to or leaning against Obama's plan for a military strike by more than a 6-1 margin.
The survey found nearly half of the 433-member House and a third of the 100-member Senate remain undecided.
Syrian President Bashar Assad also has been getting his message out. In an interview that will air Monday morning on CBS, Assad denied that he used chemical weapons on his people.