Israeli aerospace firm ELTA has received U.S. permission to export core parts of an early warning aerial control system to South Korea.

An ELTA source on Monday said Washington has lifted the export ban on the aircraft identification data link and Identification Friend or Foe systems of the U.S.-based DRS Technologies, an associate of Elta.

The Defense Acquisition Program Administration in Seoul will begin the selection process to decide on the supplier by the end of May.

ELTA is competing with American aerospace giant Boeing for the contract of South Korea's EX project, under which Seoul will buy four units equipped with the early warning systems by 2011.

Boeing and ELTA satisfy the Air Force's requirements but the Israeli firm has offered a lower price of 1.1 billion dollars a unit, compared to Boeing's 1.5 billion dollars.