Washington, Mar 12 (IANS): Vermont Senator Bernie Sanders has said that he would carry on in the race for the Democratic presidential nomination, a day after his rival and former Vice President Joe Biden widened his lead in six-state mini-Super Tuesday primaries.

"We have won the ideological debate but we are losing the debate over electability," Xinhua news agency quoted Sanders as saying on Wednesday.

"I cannot tell you how many people our campaign has spoken to who say they agree with us, but will vote for Joe because they believe he's the best to beat Donald Trump.

"Needless to say, I strongly disagree with that assertion but that's what millions of Democrats and Independents say," said the veteran politician.

Biden won Michigan, Missouri, Mississippi and Idaho on Tuesday night, extending his delegate lead to about 150 over Sanders, who won the Midwest state of North Dakota. Washington's primary election was still too early to call.

Sanders also said he would challenge Biden on a series of issues and make the case for his progressive politics when they square off for their first one-on-one debate of the cycle on Sunday in Arizona.

However, Sanders reiterated on Wednesday that his top commitment was to ensure that Trump was not re-elected in November.

Biden is still only about halfway to the 1,991 delegates a candidate needs to win the nomination after Tuesday's primaries.