The American Civil Liberties Union (ACLU) and several other groups have filed a lawsuit in an effort to strike down a new law allowing the U.S. government to intercept the phone calls and e-mail messages of people with suspected ties to terrorism.

The ACLU, Amnesty International, Human Rights Watch and other groups filed the lawsuit in U.S. District Court for the Southern District of New York on Thursday, the same day that President George Bush signed the Foreign Intelligence Surveillance Act (FISA) Amendments Act.

The new law, approved by the U.S. Senate on Wednesday, allows the U.S. National Security Agency and other intelligence agencies to conduct surveillance of a wide range of people "reasonably believed" to be outside the U.S. The law also will likely require a U.S. court to dismiss more than 40 lawsuits that have been filed against telecommunication carriers that allegedly participated in the NSA program before there was court oversight of the surveillance.

The FISA Amendments Act still allows broad, untargeted surveillance, including spying on U.S. residents who are talking with people overseas, said Jameel Jaffer, director of the ACLU National Security Project.

The law allows the "massive acquisition of U.S. citizens' and residents' international communications," Jaffer added. "It permits the government to conduct intrusive surveillance without ever telling the court who it intends to surveil, what phone lines or e-mail it intends to monitor, where the surveillance targets are located, or why it is conducting the surveillance."

The new law violates the Fourth Amendment of the U.S. Constitution, prohibiting the government from unreasonable searches and seizures, the ACLU said.

The Bush administration operated the so-called Terrorist Surveillance Program in secret for about four years before media reports brought it to light in December 2005. The program allowed the NSA, without court-issued warrants, to conduct surveillance of phone calls and e-mails of people with suspected ties to terrorism, including U.S. residents talking to overseas suspects.

Advocates of the FISA Amendments Act say the law creates court oversight of the surveillance program and makes it difficult for the NSA to target U.S. citizens unless under a court-issued warrant. The bill also makes clear that U.S. surveillance programs must be monitored by the U.S. FISA Court, said supporters, including Senator Kit Bond, a Missouri Republican and vice chairman of the Senate Intelligence Committee.

The law was "absolutely essential" to protect the U.S. against terrorism, Bond said on the Senate floor this week. Critics who say the new law will allow unrestricted surveillance of U.S. residents are "just plain, flat wrong," he added.