The chairman of the Senate Homeland Security Committee joined two top Republicans on Thursday in introducing a bill to reauthorize expiring anti-terrorism authorities.

Sen. Joseph I. Lieberman , I-Conn., is cosponsoring a measure by Jeff Sessions of Alabama, the ranking Republican on the Senate Judiciary Committee, and Christopher S. Bond of Missouri, the ranking Republican on the Intelligence Committee.

The bill would renew but not modify three expiring provisions of the anti-terrorism law known as the Patriot Act. The legislation would run through 2013.

Senate Judiciary Chairman Patrick J. Leahy , D-Vt., and Senate Intelligence Chairwoman Dianne Feinstein , D-Calif., meanwhile, want to reauthorize the expiring provisions for four years, with modifications.

The bill by Lieberman and his allies represents an attack from the right side of the political spectrum, and it is likely to slow Senate progress on reauthorizing the Patriot Act provisions. Leahy and Feinstein’s bill already was under fire from the left; civil libertarians have criticized it as an insufficient rewrite of the provisions.

“Our intelligence and law enforcement professionals need a complete and immediate reauthorization of the expiring Patriot Act provisions,” Lieberman said, adding that “recent arrests of alleged terrorists plotting attacks throughout our country clearly show that this is no time to weaken or undermine the tools that law enforcement relies on to protect America from another terrorist attack.”

The three expiring sections of the law allow the government to seek orders from a special federal court for “any tangible thing” that it says is related to a terrorism investigation, to seek court orders for roving wiretaps on terrorism suspects who shift their modes of communication and to apply for surveillance authority on “lone wolf” terrorists not necessarily connected to a larger organization.