The United States says its special forces in the Iraqi capital Baghdad have captured Abu Abbas, the leader of Palestinian hijackers who seized an Italian cruise ship in the Mediterranean in 1985.
Abu Abbas was convicted in absentia
An elderly American tourist in a wheelchair, Leon Klinghoffer, was killed during the hijacking of the Achille Lauro, and his body thrown into the sea.
Abbas eluded capture at the time but was convicted in absentia by a court in Italy for masterminding the attack.
The BBC's Ian Pannell, in Washington, says the US will regard his capture as an important victory in the war on terrorism, as well as something of a vindication of the charge that the regime of Saddam Hussein was connected to terrorist groups.
Abbas and the group he led, a faction of the Palestine Liberation Front (PLF), have been based in Iraq for the past 17 years.
a big catch for us - it's an old score to settle
Former CIA official
US Central Command said special forces, backed by US infantry, captured him on Monday night. A number of his associates were also said to have been detained during raids at several sites in the city.
A spokesman said that it was not clear whether Abbas would be extradited for trial, but added that "justice would be served".
Abu Abbas, also known as Mohammed Abbas, had been mentioned by President George W Bush as an example of the kind of figure given refuge by the former regime of Saddam Hussein.
Last week, US marines found bomb-making equipment at a 20-building complex east of Baghdad, which the Americans say was a PLF training camp. Chemicals, gas masks and AK-47s were also found at the complex.
Four PLF members, including Abbas, carried out the 1985 attack on the Achille Lauro in an attempt to secure the release of 50 Palestinian prisoners being held in Israel.
The ship was seized while sailing between the Egyptian cities of Alexandria and Port Said.
After a two day stand-off, Egypt gave free passage to the hijackers in exchange for the rest of the hostages - many of them Americans.
But the plane carrying the hijackers to Tunisia was intercepted by US Navy jets and forced to land in Italy.
Abbas's co-conspirators were sentenced to long prison terms, but he himself was freed by the Italian authorities, who said they had insufficient evidence to detain him.
However, he was later convicted in absentia of masterminding the hijacking and received five life sentences.
Now in his early sixties, Abbas has reportedly spent much of the past 17 years in Iraq.
In 1996, he apologised for Mr Klinghoffer's death, describing the killing as a mistake.