The leaders of the House and Senate intelligence committees said Sunday they believe that the Taliban has grown stronger since President Obama sent 33,000 more U.S. troops to Afghanistan in 2010.

The pessimistic report by Sen. Dianne Feinstein (D-Calif.) and Rep. Mike Rogers (R-Mich.) challenges Obama’s assessment last week in his visit to Kabul that the “tide had turned” and that “we broke the Taliban’s momentum.”

Feinstein and Rogers told CNN’s “State of the Union” that they aren’t so sure. The two recently returned from a fact-finding trip to the region, where they met with Afghan President Hamid Karzai.

“President Karzai believes that the Taliban will not come back. I’m not so sure,” Feinstein said. “The Taliban has a shadow system of governors in many provinces.”

When asked if the Taliban’s capabilities have been degraded since Obama deployed the additional troops two years ago, Feinstein said: “I think we’d both say that what we’ve found is that the Taliban is stronger.”

More than 1,800 U.S. troops have been killed in the decade-long war. About 88,000 service members remain deployed, down from a peak of more than 100,000 last year. More troops are expected to leave by the end of summer, with all combat troops gone by the end of 2014.

Persistent violence has threatened to undermine Obama’s effort to show progress in stabilizing Afghanistan at a NATO summit later this month in Chicago.

On Sunday, an Afghan soldier killed a NATO soldier before being fatally shot by return fire in southern Afghanistan, the latest in a series of attacks against foreigners blamed on government forces within their own ranks.

NATO confirmed that one service member was killed by an attacker wearing an Afghan army uniform in the country’s south and that coalition forces returned fire and killed the gunman.

But the alliance provided no details, saying an investigation was underway.

Feinstein said she would like to meet with Pakistan’s leaders to discuss the need for more help to break up the Haqqani insurgent network on the Afghan border. Congress has passed various restrictions on U.S. aid to Pakistan after Osama bin Laden was found hiding within its borders. A recent defense policy bill would withhold 60 percent of military aid if the defense secretary can’t show that the money will be effective in fighting the Taliban and ensuring that Pakistan helps with efforts to counter roadside bombings.

Rogers said he and Feinstein agree that the first step should be for the United States to designate the Haqqani group as a terrorist network and “take aggressive steps” to disrupt its operations. He said Haqqani is responsible for nearly 500 U.S. deaths and continues to operate outposts along the Afghan-Pakistani border.

Republicans have turned the war into a campaign issue, despite waning public support for the conflict, by criticizing Obama for setting an end date for U.S. combat operations.

“We ought to have a hard discussion about saying, listen, war is when one side wins and one side loses,” Rogers said. “And if we don’t get to that calculation of strategic defeat of the Taliban, you’re not going to get to a place where you can rest assured that you (U.S. troops) can come home and a safe haven does not re-establish itself.”