The top U.S. and NATO commander in Afghanistan says ties between coalition and Afghan forces remain strong and that the military campaign to deny al-Qaida safe haven in the country is on track, despite recent setbacks.

U.S. Marine Corps General John Allen told the U.S. House of Representatives panel Tuesday that in any counter-insurgency situation, there will be successes and setbacks — often at the same time and in the same place. He said morale among U.S. forces remains high, despite what he called several recent “heart-wrenching” events.

The commander said that although “there is much hard and deadly work to do…the progress is real and sustainable.” He said U.S. and Afghan troops have severely degraded the insurgency and that Afghan forces are ready to take the lead when it comes to security.

General Allen told the panel 60 coalition troops have been killed in combat since January, 13 of them “at the hands of what appear to have been Afghan security forces.”

NATO is in the process of handing over security control to Afghan troops, with all foreign combat troops set to leave Afghanistan by the end of 2014.

White House spokesman Jay Carney said Tuesday he cannot provide any numbers on the pace of the U.S. pullout. He said the troop withdrawal will be a topic of intense discussions at next month's NATO summit in Chicago, but that people should not expect any new announcements on the issue.

General Allen's testimony comes at a time when several lawmakers — Republicans and Democrats alike — say the financial and human costs of the long war in Afghanistan are too high. It also comes after a U.S. soldier allegedly killed 16 Afghan villagers during a March 11 shooting spree in the southern province of Kandahar and after violent protests throughout Afghanistan against the inadvertent burning of Qurans at a U.S. airbase killed 32 Afghans.

U.S. and Afghan officials are negotiating the terms of the pact that would define the U.S. presence in Afghanistan after the withdrawal.

Afghanistan vice president Mohammad Qasim Fahim on Tuesday reassured Afghans that any strategic partnership deal with the United States will respect the sovereignty of the country, saying a U.S.-Afghan agreement will be based on the interests of both nations.

Two major obstacles to the negotiations have been the transfer of U.S. detention centers to Afghan authorities and night raids conducted by coalition troops.

Earlier this month, U.S. and Afghan officials reached an agreement on the prison issue, giving Afghans control of detainees within six months. Talks are now underway on the issue of night raids.

Also, Afghan Foreign Minister Zalmai Rassoul is in Washington this week for talks with U.S. officials on the strategic deal.