Signatures seeking to recall a third and fourth Republican state senator were filed this week.

About 24,000 signatures were filed Monday to recall Sen. Luther Olsen (R-Ripon) and an estimated 23,000 signatures were filed Tuesday to recall Sen. Sheila Harsdorf (R-River Falls). That's far more than the 14,733 needed to recall Olsen and 15,744 needed to recall Harsdorf.

Also Tuesday, Rep. Fred Clark (D-Baraboo) said he would make an announcement about the recall effort against Olsen at noon Thursday at the Baraboo Civic Center. Clark is expected to run against Olsen.

Recall efforts are under way against four other Republican and eight Democratic state senators. Recall organizers have to collect signatures equaling 25% of the total vote for governor in November's election in each Senate district.

Three of the campaigns against Democrats have said they planned to file signatures this week.

Dan Hunt, chairman of a group trying to recall Sen. Robert Wirch (D-Pleasant Prairie), says his group has more than 20,000 signatures, well over the 13,537 needed.

Chad Fradette, head of one of two committees to recall Sen. Dave Hansen (D-Green Bay), said the two groups had collected 18,000 to 19,000, more than the 13,852 needed.

Kim Simac, head of the recall effort against Sen. Jim Holperin (D-Conover), couldn't be reached for comment, but she's said her group would also file this week.

Democrats are seeking to recall Republicans because of their votes for Gov. Scott Walker's budget-repair bill limiting public worker union bargaining. Republicans are targeting Democrats because 14 Democratic senators left the state for three weeks to stall a vote on the bill.

The recalls of the Republican senators face a May 2 deadline to deliver the signatures; most of the recalls of Democrats have deadlines next week.

After the signatures are filed, the Government Accountability Board has 31 days to verify them and schedule a recall election - but that schedule can be delayed by court challenges and other factors.