ST. PAUL, Minn. -- Democrat Al Franken withdrew 633 challenges to ballots Wednesday in Minnesota's U.S. Senate race in what could be a first step toward a quicker conclusion to the recount. 

Franken's attorney, Marc Elias, said many more withdrawals are likely. An attorney for Republican Norm Coleman said he may follow suit soon. 

Any reduction in the pile of challenged ballots -- more than 6,000 so far -- will alleviate work for the canvassing board that meets Dec. 16 to begin examining those ballots. 

Coleman defeated Franken in the election by 215 votes, a margin so small that it triggered an automatic recount. 

By Wednesday night, Coleman led by 316 votes, according to recount totals posted by Minnesota's secretary of state. But that apparent lead was far overshadowed by the thousands of ballots challenged by the two campaigns. 

Each candidate has challenged about the same number of votes. 

The Franken campaign mailed a letter to Secretary of State Mark Ritchie on Wednesday with a list of specific challenges to discard. "If there are challenges that are without merit, it doesn't do either side any good to have them considered," Elias said. 

Coleman's attorney, Fritz Knaak, said the Republican's campaign has also been considering a withdrawal of some challenges but wouldn't do so until after Friday, the deadline for the recount to end. 

"We don't want to send the wrong message to our volunteers still working at the recount sites," Knaak said. 

Challenges range from ballots with votes for more than one candidate to many that simply had a pen scribble somewhere on the ballot. The number of challenges far exceeds the margin between the two men, making it difficult to pin down which candidate the recount is favoring.