Congress approved a measure Friday that would renew expansive U.S. surveillance authority for five more years, rejecting objections from senators who are concerned that the legislation does not adequately protect Americans' privacy.

The bill passed the Senate, 73 to 23. The House approved it in September, and President Barack Obama is expected to sign it before the current authority expires Monday.

The lopsided Senate vote authorized a continuation of the government's ability to eavesdrop on communications inside the United States involving foreign citizens without obtaining a specific warrant for each case. The surveillance under the Foreign Intelligence Surveillance Act, or FISA, has been credited with exposing several plots against U.S. targets, but it also has drawn fire from civil liberties advocates.

"It produced and continues to produce significant information that is vital to defend the nation against international terrorism and other threats," said Senate Intelligence Committee chairwoman Dianne Feinstein, D-Calif., who urged her colleagues to approve the extension without amendment, so it would not need to be sent back to the House for a vote. Ms. Feinstein said about 100 arrests have occurred in terrorism-related plots over the past four years -- 16 in the past year -- and that electronic surveillance played a role in some of them.

Senators devoted much of Thursday to debating proposed privacy amendments to the bill, which renews a key provision of the FISA Amendments Act of 2008. The Bush-era provision expanded the government's surveillance authority to intercept electronic communications in the United States without a warrant if the targets are foreigners overseas. The surveillance is conducted under a blanket approval issued once a year by a special court if that court is satisfied that the government's targeting procedures will work and that privacy protections are adequate.

But the emails and phone calls of Americans who communicate with the foreigners are also being swept up. A number of senators voiced concerns that intelligence agencies could search the data for particular communications of U.S. citizens without a warrant.

The measure's leading Senate critic, Oregon Democrat Ron Wyden, agreed to drop his insistence that the government obtain a warrant for such searches in exchange for the Senate leadership's assurance that it would hold a vote on a Wyden amendment aimed at assessing the law's privacy impact on Americans.

Mr. Wyden's amendment got 43 votes Friday. Three other attempts to add safeguards and make other changes were defeated Thursday.