Dozens of groups from across the political spectrum are urging Congress to reform the federal government's bulk surveillance practices as divisions emerge on Capitol Hill over how to handle those spy programs ahead of a June 1 deadline.

The groups oppose a proposal backed by Senate Majority Leader Mitch McConnell (R-Ky.) to renew the National Security Agency's current authority to conduct a daily dragnet of phone records and instead want changes written into the federal Patriot Act, such a those included in a bipartisan bill now moving through the House of Representatives. The groups signing a letter to congressional leaders Wednesday run the ideological gamut, from watchdogs like the American Civil Liberties Union and Amnesty International to liberal groups such as the NAACP and People For the American Way and conservative organizations such as FreedomWorks and Gun Owners of America.

"Policymakers on both sides of the aisle, along with members of the public, have consistently urged Congress to take action to restore accountability, transparency, and faith in intelligence agencies," the letter reads. "Despite this, Congress has yet to enact meaningful reforms that would end bulk collection, preserve privacy, and protect human rights."

Congress has scheduled a little more than two weeks of work before the current law expires. The House is moving forward with a reform bill, known as the USA Freedom Act, that could get a final vote there as soon as next week. Senate leaders, however, have signaled that they do not plan to move as swiftly to implement reforms. Instead, McConnell said Tuesday he expects to take up complex trade legislation next week, with could leave limited time for consideration of any reforms before the deadline expires.

In lieu of the reform bill, McConnell has co-authored a bill with Senate Intelligence Committee Chairman Richard Burr (R-N.C.) that would reauthorize current bulk surveillance programs for five additional years without any reforms, and he has made preparations to bring that bill to a floor vote without committee consideration. Congressional opponents of the NSA's practices have said they fear McConnell's moves are calibrated to force Congress to act shortly before the deadline with limited time to debate new constraints.

McConnell on Tuesday said he intended to move forward with his own bill, not the House bill, though he signaled it would be open for amendment. "What I've said is we're going to try to do something to avoid expiration at the end of the month," he said. "Exactly how that plays out, will be determined, in part, by how much time is left to achieve it."

Democratic leader Harry M. Reid (Nev.) urged McConnell to take up the House legislation as soon as it is passed. "The wise thing to do would be to pass that bill because I think there is significant votes in the Democratic and Republican caucuses here in the Senate to do just that," he said, adding that a "vast majority" of the Republicans "don't want an extension of the old bill; they want something new."

The groups strongly oppose the McConnell-Burr bill in Wednesday's letter, saying a flat renewal of the spying authority would "fail to address the deleterious impact that mass surveillance conducted under Section 215 continues to have on our privacy, economy, and democracy."

"In the absence of meaningful reform, it is unacceptable to rubber stamp reauthorization of an authority that the government has used to spy on millions of innocent Americans," the letter reads.

In addition to ending bulk surveillance of phone "metadata," which includes the numbers dialed, call times and durations, the House bill would require the nation’s secretive surveillance court to provide a public summary or redacted version of significant opinions. It would also grant technology companies more leeway to report on the scale of national security requests for data they receive, and it would provide for an advocate for the public’s privacy rights at the Foreign Intelligence Surveillance Court, which generally hears only the government’s side of an argument.

Ellen Nakashima contributed to this report.