US military trainers will be invited back into Pakistan “as early as April or May,” but the nation has ruled out allowing CIA drones back into the country, Fox News reported. The stipulations will include no covert CIA or military operations on the ground in Pakistan, and no unauthorized incursions into its airspace. Drones”can never return,” a senior Pakistani official told Fox News. “They will never be allowed back, at Shamsi or anywhere else,” the official added. In return, Pakistan would allow back US military trainers, including special forces teams, and a resumption of close cooperation with the CIA in targeting militants who use the Pakistani side of the border as a safe haven. It would also reopen the Torkham and Chaman border crossings into Afghanistan, which have been closed to NATO supply convoys since the attack. “After this is presented to the Americans, a lot could happen very quickly,” the senior official told Fox News, speaking on the condition of anonymity. Islamabad also would reopen its doors to high-level U.S. diplomats after an embarrassing snub this week to President Obama’s special envoy to the region, Marc Grossman, who was denied his request to visit Pakistan in the middle of his tour of South Asia. “We understand the government of Pakistan is still working on its review of U.S.-Pakistan relations, and we have not yet received a formal report from the government,” Pentagon spokesman Capt. John Kirby said in an emailed statement.