U.S. Sen. Al Franken announced today that he raised $1.985 million in the first quarter of 2013 for his re-election campaign.

The strong fundraising quarter brings Franken's total cash on hand to $2.03 million, as Republicans continue to sort out who will challenge the first-term senator from Minnesota.

U.S. Reps. John Kline and Erik Paulsen of Minnesota, Minnesota investment banker Mike McFadden and talk radio host Jason Lewis have been mentioned as potential challengers to Franken.

Kline, who represents the state's Second Congressional District, raised $257,742 during the first quarter and has $750,000 total banked, according to documents filed with the Federal Election Commission.

Paulsen, who represent the Thrid Congressional District, has yet to report his first quarter fundraising totals, but he finished the 2012 election cycle with about $694,000 in the bank.

Franken's fundraising totals do not include proceeds from a fundraiser that comedian and late night television Conan O'Brien hosted for him in California last weekend.