The United States will soon suffer a catastrophic cyberattack if it doesn't act now to prevent it, the chairman of the House Intelligence Committee warned Thursday.

"The clock is ticking and winding down," Rep. Mike Rogers, R-Michigan, said at a hearing on the security threats facing the United States.

Speaking to the nation's top intelligence officials, Rogers said that, "given classified briefings that we've had, discussions with all of you and your counterparts ... that a cyberattack is on its way. We will suffer a catastrophic cyberattack."

The committee's top Democrat, Rep. Dutch Ruppersberger of Maryland, said foreign governments -- in particular China and Russia -- steal American intellectual property to gain a competitive edge.

Director of National Intelligence James Clapper accused China of "the greatest pillaging of wealth in history, if you tote up the value of the intellectual property that has been stolen."

The urgency and severity of the problem was also echoed by FBI Director Robert Mueller. "The cyberthreat will equal or surpass the threat from counterterrorism in the foreseeable future," he said.

Both Rogers and Ruppersberger said now is the time for Congress to act and pass cybersecurity legislation.

Defense Secretary Leon Panetta's comments on Wednesday that the United States and NATO want to end their combat mission in Afghanistan next year, transitioning primarily to a training role, drew some sharp comments during the hearing.

Some Republican members of Congress said it is premature to make such a decision before it is clear Afghanistan forces are able to defend the country.

The Obama administration has said it wants all U.S. combat forces out of Afghanistan by the end of 2014.

Rep. Michael Conaway, R-Texas called Panetta's statement "startling." And Rep. Mac Thornberry, R-Texas, said he is concerned about the announcement and wondered if there is a good reason for U.S. forces to be in Afghanistan.

CIA Director David Petraeus responded there is, citing the need to prevent Afghanistan from ever again becoming a safe haven to extremists who could attack the United States as they did on September 11, 2001.

But Petraeus also said Panetta's comments had been way "over-analyzed."

Petraeus pointed out he was commander of forces in Afghanistan when the policy was adopted to make the transition. "To do that we embarked on a policy of transition progressively over time. ... What Secretary Panetta was discussing was indeed this progressive transition, and if you're going to have it completed totally by the end of 2014, obviously somewhere in 2013 you have had to initiate that in all of the different locations so that you can complete the remaining tasks," Petraeus explained.

Another contentious issue was the possibility the Obama administration will release five Afghan prisoners held at Guantanamo Bay as a confidence-building measure in its effort to open peace talks with the Taliban.

Rogers maintained the United States would be "crossing a dangerous line" by pursuing such a plan.

He got both Petraeus and Clapper to acknowledge the Taliban continues its practice of political assassinations, that the Taliban wants to go beyond its theater of operation and that it has ties to al Qaeda.

"So you can see where maybe someone who looks at all of this information might scratch our head and wonder, given the fact that after the negotiations started they were committing acts of political assassination to undermine all of the work, all of the sacrifice of the United States military and intelligence on the ground, why some of us might get a little bit cranky about what we're doing when we talk about reconciliation," Rogers said.

Clapper said the administration doesn't harbor any illusions about the effort, but thought it was worth pursuing. He stressed no final decisions have been made.

Rogers called on the administration to reconsider its approach.

On Iran, Rogers told CNN in an interview on Wednesday that the U.S. military needs to do more to scare Iran away from pursuing nuclear weapons. He alluded to that during the hearing when questioning Clapper.

"The narrative is they have to believe we are serious when we say all options are on the table," Rogers said. "I'm not convinced we're there yet."

Committee members also expressed concern about the foiled attempt by Iran to assassinate the Saudi ambassador to the United States in Washington.

Clapper said the Iranians might be pursing terrorist activities because of their belief that the Arab Spring uprisings give them an opportunity to extend their reach. He also said Iran might feel "somewhat under siege," because of the intensified international sanctions placed on it because of its nuclear program.

When Rep. Mike Thompson, D-California, asked if this sort of activity could "raise its ugly head again," Clapper responded that the Iranians and their proxies "have been as aggressive as they ever have been in the last decade or so. So I expect we'll see more of this."