Updated

A bipartisan group of senators are unveiling legislation that would end the National Security Agency's collection of millions of Americans' phone records.

Three Democrats — Ron Wyden, Mark Udall and Richard Blumenthal — and Republican Rand Paul discussed their bill at a Capitol Hill news conference on Wednesday. They said the measure also would overhaul the secret federal surveillance court, allow constitutional challenges and create an advocate to argue against the government.

The lawmakers said the legislation is necessary to ensure the privacy rights of Americans. Disclosures about the NSA programs this summer raised questions about protection of civil liberties. The Obama administration has insisted the spying was a necessary tool to fight terrorism.

The legislation comes on the eve of a Senate hearing with top intelligence officials.