The State Department said it had seen reports of the episode, but also noted Nigeria's hints that it had no interest in buying ballistic technology from Pyongyang.

"We'd welcome a decision to turn down any such offers from North Korea," said spokesman Richard Boucher.

"We want to stop North Korea's missile activities. And we've gone to many countries to try to encourage them not to buy. So that would be the right decision, if that's indeed the decision they've made."

A spokesman for Nigeria's Vice President Atiku Abubakar earlier said that Pyongyang wanted to sign a memorandum of understanding with Nigeria on developing missile technology, training and the manufacturing of ammunition.

"They were just trying to get us interested. There hasn't been any interest shown on our side," Onu Kaba Ojo said.

Ojo confirmed that Nigeria was seeking ballistic missile technology and said that the issue had come up at a meeting on Tuesday between Abubakar and his North Korean counterpart Yang Hyong-Sop, although no deal had been signed.

Nigeria's President Olusegun Obasanjo met Hyong-Sop on Wednesday, but defence matters were not addressed, a presidential spokeswoman said.

The United States, which considers Nigeria a friend, would be highly irritated by any decision by Abuja to acquire North Korean ballistic missiles.

Washington is locked in a bitter political standoff with its Stalinist foe over its nuclear ambitions and international arms sales.

Kim Jong-Il's regime -- which US President George W. Bush has dubbed a member of an "axis of evil" -- earns much of its hard currency by selling and swapping missile and weapons secrets.

North Korea has developed missiles capable of carrying warheads as far as Japan and is reported to have shared its technology with Libya, Syria, Iran, Yemen, Pakistan and Saddam Hussein's former Iraqi regime.

WAR.WIRE