Former U.S. Attorney Michael Sullivan is kicking off what he's calling a grass-roots effort to collect the signatures needed to get on the Republican primary ballot for Massachusetts' special U.S. Senate election.

Sullivan said in a statement Thursday that for the past 10 days he has been giving serious consideration to entering the race.

He said he wants to see if he can collect the required 10,000 voter signatures before the Feb. 27 deadline using volunteers instead of paid gatherers.

Also Thursday, Republican Sean Bielat filed papers with the Federal Election Commission to form the "Sean Bielat for Senate" committee.

The committee's treasurer told The Associated Press that Bielat is running, but a former campaign aide who spoke to Bielat on Thursday later told the AP that he's formed an exploratory committee, but hasn't made a final decision.