U.S. President Barack Obama on Monday asked supporters to make donations to help Democratic candidates win the 15 Senate seats that were still "up for grabs."

"I'm counting on the DSCC to win the 15 Senate seats still up for grabs over these last 15 days," Obama said in an e-mail for the Democratic Senatorial Campaign Committee (DSCC). "But they need 919,100 dollars before midnight Thursday to unleash a massive get-out-the-vote blitz this weekend."

Republicans need to add at least 10 seats to regain the Senate majority in the upcoming mid-term elections. Most analysts do not see that scenario as something likely, even though they generally anticipate a narrowed seats gap between the two parties after the Election Day on Nov. 2.

"The DSCC has already begun to shift momentum in our favor in critical races -- but Republicans only need to win 10 of the 15 seats up for grabs to take the majority," Obama wrote. "But if you keep moving forward in the face of difficulty, we will win this election."

Heading into the last two weeks before the Election Day, Obama is traveling to a host of states to energize voters and build up turnout among his supporters.

According to his schedule, the president will fly to Portland, Oregon on Wednesday to attend a fundraiser and rally there for Democratic nominee for governor John Kitzhaber. He will be in Washington state on Thursday to deliver remarks at a rally for Senator Patty Murray. He will then attend fundraisers for Senator Barbara Boxer and Senate Majority Leader Harry Reid in their respective home states on Friday.