WASHINGTON -- In an extraordinary breach of congressional decorum, a Republican lawmaker shouted "You lie" at President Barack Obama during his speech to Congress Wednesday.

The incident came directly after Obama said, "There are also those who claim that our reform effort will insure illegal immigrants. This, too, is false. The reforms I'm proposing would not apply to those who are here illegally."

"You lie!" Rep. Joe Wilson, R-S.C., shouted from his seat on the Republican side of the chamber.

Wilson's shout drew immediate condemnation from both sides of the aisle, ultimately leading him to apologize. Wilson tried to call Obama to apologize in person, but ended up speaking to White House chief of staff Rahm Emanuel.

The contrite congressman, "expressed his apologies" to Emanuel, not the president at whom he had shouted a few hours earlier, Wilson's office said.

By that time, Wilson's House Web site had crashed and he had taken a brutal beating on his Twitter page for breaching protocol and good manners during a presidential speech to a joint session of Congress.

"This evening I let my emotions get the best of me when listening to the president's remarks regarding the coverage of illegal immigrants in the health care bill," Wilson said in a written statement. "While I disagree with the president's statement, my comments were inappropriate and regrettable. I extend sincere apologies to the president for this lack of civility."

White House spokesman Bill Burton told FOX News Thursday Wilson's apology has been accepted.

Immediately following the shout, Wilson seemed to sense that he had fouled up. Wilson appeared to consult his Blackberry for much of the rest of Obama's speech. He shook his head defiantly after several of the president's statements. When Obama finished, Wilson bolted from the chamber.

In the hours after Obama's speech, Wilson's Democratic opponent, former Marine Rob Miller, raised close to $100,000 in online contributions, Democratic sources told FOX News.

Wilson's wasn't the only interruption during Obama's speech, but it was the most notable.

Reaction to the outburst included criticism from members of Wilson's own party.

"Anybody who would cat-call the president of the United States addressing this body is very, very inappropriate, and he will hear from a lot of us about that," Rep. Jerry Lewis, R-Calif., told FOX News Radio.

Sen. John McCain, R-Ariz., said Wilson's behavior was "totally disrespectful. There is no place for it in that setting, or any other, and he should apologize for it immediately."

Democratic Sen. Dick Durbin of Illinois called it "crude and disrespectful."

And Democratic Sen. Jim Clyburn, also of South Carolina, said Wilson "went beyond heckling."

"That was probably one of the most-insulting things I've ever seen," Clyburn told FOX News. "The people of South Carolina are not well-served by that."

House Majority Leader Steny Hoyer, D-Md., said "I have never in my 29 years heard an outburst of that nature with reference to a president of the United States speaking as a guest of the House and Senate."

"It was a shameful act," he told WTOP radio.

Hoyer said he'll work with GOP lawmakers to decide whether to punish Wilson.

House Speaker Nancy Pelosi, who spoke to FOX News before learning who delivered the yell, said she didn't intend to move to sanction anyone for it.

The Associated Press contributed to this report.