20091228

ABUJA (Reuters) - The family of a Nigerian man who tried to blow up a U.S. passenger airliner said on Monday they had lost contact with him while he was studying abroad and reported his disappearance to security agencies two months ago.

In the United States, authorities tightened airline security and questions were raised about how a man suspected of ties to militants was able to smuggle explosives aboard a transatlantic flight.

Umar Farouk Abdulmutallab, 23, was charged on Saturday in the United States with trying to blow up Northwest Airlines flight 253 as it approached Detroit from Amsterdam on Christmas Day with almost 300 people on board.

In a statement to Nigerian media, the Mutallab family said: "His father, having become concerned about his disappearance and stoppage of communication while schooling abroad, reported the matter to Nigerian security agencies about two months ago and to some foreign security agencies about a month and a half ago."

It said the fact that he had ended communication with his family was "completely out of character and a very recent development".

Nigerian media had quoted family members as saying the father had been uncomfortable with his son's "extreme religious views" and had reported him to the U.S. embassy.

Dutch military police said they were investigating the possibility that Abdulmutallab might have had help from an accomplice before boarding the flight at Amsterdam's Schiphol Airport.

A U.S. couple on the flight, Kurt and Lori Haskell, told Reuters and other news agencies they saw a tall, well-dressed man aged about 50 with Abdulmutallab on Friday morning.