The U.S. has acquired an important new asset in its diplomatic battle with North Korea over nuclear weapons. In what appears to be a major intelligence coup, the CIA last month recruited a foreign nuclear scientist who worked on North Korea's nuclear-weapons program, two U.S. officials and a foreign-government source tell TIME. The scientist has been relocated to the U.S. and has provided valuable information on the "location, degree of development in capabilities, where they are, how far along they are in developing multiple-weapons capability," a U.S. official said. His information, it is hoped, will be especially valuable in the next round of talks with North Korea. Until now, American officials have been largely in the dark about North Korea's exact nuclear capabilities, especially since the country ejected international weapons inspectors and withdrew from the Nuclear Non-Proliferation Treaty in January. The CIA, whose spokesman declined to comment, had earlier concluded that North Korea has developed at least two nuclear devices, U.S. officials say. But the scientist has helped confirm that the North Korean program is much further along than that. "It's one thing to make one or two," says the U.S. official. "It's another thing to have a process in place to make hundreds. They're on their way to be able to make hundreds within the next couple of years."