KUALA LUMPUR, Malaysia — The body of Kim Jong Nam, the estranged half brother of North Korea’s leader, was released to the North on Thursday, a month after his airport murder unleashed a diplomatic battle.

After negotiations that he described as ‘‘very sensitive,’’ Prime Minister Najib Razak said Malaysia agreed to release the body in exchange for the return of nine Malaysians held in North Korea’s capital. There were no details on what led to the breakthrough, but North Korea appeared to win some important concessions: custody of the body and the release of two suspects who had been holed up in its Kuala Lumpur embassy.

The poisoning of Kim, which took place amid travelers in a terminal at Kuala Lumpur’s airport on Feb. 13, has prompted speculation that North Korea dispatched a hit squad to assassinate its leader’s estranged older brother.

Associated Press