Presumptive U.S. Democratic presidential nominee Barack Obama Saturday confirmed he has chosen Delaware Sen. Joe Biden as his running mate.

A text message from the campaign of the Illinois senator bearing the news was sent out to field workers early Saturday, CNN reported.

The text message sent at 3 a.m. EDT read, "Barack has chosen Senator Joe Biden to be our VP nominee."

An e-mail received by campaign workers read, "Joe and I will appear for the first time as running mates this afternoon in Springfield, Illinois -- the same place this campaign began more than 19 months ago," the New York Times reported.

The biggest strength for Biden, 65, is foreign policy. His is the chairman of the Senate Foreign Relations Committee and is on a first-name basis with foreign leaders from around the world. Unlike Obama, he initially supported the Iraq invasion, voting to authorize the war. But eventually he became a strong critic of President George W. Bush's Iraq position, the newspaper said.

Biden is also Catholic, although he favors abortion rights. Up for re-election this year, he would likely run for both positions, the Times said.

The campaign of presumptive Republican presidential nominee, John McCain was quick to react to the news.

"There has been no harsher critic of Barack Obama's lack of experience than Joe Biden," said a statement from McCain campaign spokesman Ben Porritt, CNN reported.

The statement went on to say Biden "has strongly argued in his own words what Americans are quickly realizing -- that Barack Obama is not ready to be president."