House Democrats promised an agenda of improving the economy, ending the war in Iraq and expanding access to health care after gaining at least 18 additional seats in Tuesday's elections, ballooning the size of the party's congressional majority to its largest since 1994.

"Our increased numbers in the House will better enable us to work closely with our new president for a vision for America and for a plan to succeed," House Speaker Nancy Pelosi said at a news conference on Capitol Hill. "With our added numbers, more numbers in the House, more in the Senate and a Democrat in the White House, we have an opportunity, we have a responsibility, and the American people should and will hold us accountable."