Four Wisconsin Republican lawmakers challenge recall signatures MADISON, Wis (Reuters) - Four Wisconsin lawmakers targeted for possible recall later this year filed challenges on Thursday to the validity of thousands of signatures gathered to force the special elections, the state's Government Accountability Board said. Organizers of the drive to recall the four Republican state senators submitted more than 18,000 pages of signed petitions with the board last month. Thursday was the deadline for the four lawmakers, including Senate Majority Leader Scott Fitzgerald, to lodge objections with the board. In a statement, Fitzgerald cited "a wide range of irregularities, errors and outright falsehoods" in the petitions submitted to force him to defend his seat. He said he planned to challenge 4,300 of the signatures, which could be enough to derail the effort to unseat him. All four Republicans supported the controversial curbs on public-sector union collective bargaining powers that were enacted in Wisconsin last year. The measure, which greatly reduces the power of most public-sector unions in the state, triggered nine recall elections of state senators last summer. Two Republican senators were recalled. Critics of the law have also targeted Governor Scott Walker and Lieutenant Governor Rebecca Kleefisch, both Republicans, for possible recalls later this year. Walker has until February 27 to challenge the petitions seeking his recall, while Kleefisch has until March 5. If the board verifies enough signatures against any of the four senators targeted in this second wave of recalls, it will call a special election that could alter the balance of power in the state Senate, where Republicans hold a 17-16 majority. Recall petitioners now have five days to rebut the challenges, after which the officeholders will have two days to reply, according to state law. The Government Accountability Board then has until March 19 to verify the recalls. Until then, the board will review the challenges and continue to review petitions. Since recall organizers submitted what they said were about 1.9 million total signatures, supporters of the six targeted Republicans have asked volunteers to help comb through the thousands of petition forms posted online. Editing by James B. Kelleher and Greg McCune