Updated

President Bush will address the nation about Iraq on Sunday evening, his first speech from the Oval Office since he announced the beginning of the U.S.-led invasion in March 2003.

The address at 9 p.m. EST comes on the heels of a two-week, four-speech blitz to build support for a war that a majority of Americans now say was a mistake.

The White House said it was asking television networks for live coverage of the president's address, expected to run less than 20 minutes.

"The Iraqi people have just concluded a historic election, and we now are entering a critical period for our mission in Iraq," White House press secretary Scott McClellan said Friday.

"The president will talk about the importance of our mission and the way forward in 2006," he said.

In his four speeches, Bush sought to explain his Iraq policy more clearly — conceding that things have not gone as smoothly as he had hoped and emphasizing that much work needs to be done. The speeches brought forth an estimate from the president that 30,000 Iraqis have been killed in the invasion and its bloody aftermath.

More than 2,150 members of the U.S. military have died since the beginning of the war, according to an Associated Press count.

Bush began the series on Nov. 30 at the U.S. Naval Academy in Annapolis, Md., by focusing on the progress in training Iraqi security forces. That was followed by an address to the Council on Foreign Relations, an independent think tank, about rebuilding Iraq's economy.

On Monday, Bush appeared before Philadelphia's World Affairs Council and emphasized efforts "to help the Iraqi people build a lasting democracy in the heart of the Middle East." In his fourth speech, before the Woodrow Wilson International Center for Scholars, a nonpartisan forum for the study of world affairs, Bush said the responsibility for invading Iraq based in part on faulty weapons intelligence rested solely with him.

"It is true that much of the intelligence turned out to be wrong," Bush said. "As president, I'm responsible for the decision to go into Iraq."

Iraqi authorities worked Friday to tally millions of ballots cast on Thursday to elect a new, four-year parliament. The election commission did not provide any figures on how many of Iraq's 15 million voters cast ballots, but officials estimated turnout could have been as high as 70 percent.