Pakistan's air force escorted Iranian negotiators home from inconclusive peace talks with the U.S. last weekend, launching a major operation after the Iranians said Israel might seek to kill them, three sources told Reuters.

Pakistan deployed some two dozen jets in the escort, as well as the force's Airborne Warning and Control System for aerial surveillance to ensure the safety of the delegation back from Islamabad, said two Pakistani sources with knowledge of the operation.

One said similar security protection would be provided for subsequent talks if the Iranians ask for it, "otherwise Pakistani aircraft would receive them in Pakistan airspace".