By Sayed Salahuddin , KABUL -- The United States and Afghanistan signed a deal on night military operations on Sunday, resolving a major source of friction between President Hamid Karzai and Washington. The agreement removes a key obstacle to a long-term strategic partnership between the two countries, including a U.S. military presence in Afghanistan after 2014, when all foreign combat troops are set to leave the country. Karzai, who has led Afghanistan since U.S.-backed Afghan forces overthrew the Taliban in 2001, has repeatedly called for an end to the raids, calling them a clear violation of Afghan sovereignty. But U.S. military officials have long hailed the effectiveness of night operations, during which many suspected insurgents -- and their commanders -- have been arrested. Under the deal , a newly formed national force -- the Afghan Special Operations Unit -- will have the authority to search houses and private compounds and arrest suspected insurgents, Afghanistan's Defense Minister Abdul Rahim Wardak said Sunday. U.S. forces will provide support "only as required or requested," according to the agreement, which was signed by Wardak and General John R. Allen, the commander of the U.S. forces in Afghanistan. "This is ... a landmark day for the rule of law in Afghanistan," Allen said during a signing ceremony. "This means that Afghan security forces operating under Afghan law will now be responsible for capturing and detaining the terrorists who try to kill and wound the innocent people of Afghanistan." Many Afghans in the south and east