AFP file Nidal

The U.S. State Department once branded Abu Nidal the world's most dangerous terrorist — and his presence in Baghdad was one factor in Washington's branding of Iraq as a state supporting terrorism.

For more than two decades, the chain-smoking schoolteacher-turned-terrorist — born Sabri al-Banna in 1937 — struck targets from Paris to Pakistan. His followers bombed American airliners, mowed down travelers in airports, machine-gunned sidewalk cafes and synagogues and blew up hotels. He also assassinated a string of Palestinian moderates and two top aides of Yasser Arafat after splitting with the PLO, which he accused of abandoning the struggle against Israel.

His most notorious — but not most fatal — attacks were twin assaults on the Israeli airline El Al's ticket counters at Rome and Vienna airports on Dec. 27, 1985. Eighteen people were killed and 120 wounded.

Abu NIdal's trail of terror Abu Nidal's radical Palestinian faction has been blamed for killing or wounding nearly 1,000 people in 20 countries since 1973. Here are some of biggest and best-known: Jan. 29, 1994 — Abu Nidal followers shoot dead Jordanian diplomat Naeb Imran Maaytah outside his embassy in Beirut. Jan. 16, 1991 — Abu Nidal's guerrillas kill two of PLO leader Yasser Arafat's top aides in Tunis, the PLO's headquarters-in-exile: Salah Khalaf (known as Abu Iyad), Arafat's long-time deputy and friend, and Hayel Abdel-Hamid (code-named Abu Hol), the PLO's security chief. July 11, 1988 — Five gunmen attack the Greek cruise ship City of Poros, killing nine people and wounding 98. Sept. 6, 1986 — Two gunmen open fire on the Neve Shalom synagogue in Istanbul during Sabbath services, killing 22 Jewish worshippers and wounding six. Sept. 5, 1986 — A Pan Am jet carrying 358 people is hijacked at Karachi Airport. Twenty people are killed when security forces storm the Boeing 747. April 2, 1986 — A bomb explodes aboard a TWA Boeing 727 as the plane approaches Athens airport. Four passengers killed. Dec. 27, 1985 — Eighteen people are killed and 120 wounded in simultaneous attacks on El Al ticket desks at Rome and Vienna airports by seven Abu Nidal gunmen. Nov. 23, 1985 — An Egyptian airliner with 97 passengers is hijacked to Malta by four gunmen who kill six passengers. Sixty passengers die in shootout when Egyptian commandos storm the plane. July 11, 1985 — Two bombs kill eight people and wound 89 in Kuwait. The attack is seen as part of Abu Nidal's campaign to blackmail the Gulf Arab states into paying him not to attack them. April 10, 1983 — Issam Sartawi, a leading PLO moderate and Arafat's main link to Israeli left-wingers, is shot dead during a Socialist International conference in Lisbon. Aug. 9, 1982 — Two gunmen attack Goldenberg's, a restaurant in Paris' Jewish quarter, killing six people and wounding 22. June 18, 1982 — Kamel Hussein, head of the PLO's Rome office and a close associate of Arafat, is killed when his booby-trapped car explodes in the Italian capital. June 2, 1982 — Israel's ambassador in London, Shlomo Argov, is critically wounded by Abu Nidal gunmen. Israel uses the assassination attempt as the pretext to invade Lebanon to crush the PLO three days later. June 1, 1981 — Gunman kills Naim Khader, the PLO's representative to the European Community, in Brussels. Jan. 5, 1978 — Said Hammami, the PLO representative in London and key moderate who met with Israeli left-wingers, is shot dead in his London office. Oct. 8, 1974 — A TWA airliner flying from Israel to Greece is blown up by a bomb over the Aegean Sea, killing all 88 people aboard. Dec. 17, 1973 — Five terrorists set a Pan Am Jet on fire at Rome Airport with thermite bombs, killing 32 passengers.

There have been reports Abu Nidal was ill, and illness might have led him to take his own life, said Yossi Melman, an Israeli terrorism expert who wrote a book on Abu Nidal.

But Abu Nidal could also have been assassinated, perhaps by one of his own men in the internal feuds for which his organization is known — or perhaps by an Iraqi government fearful he knew too much about its operations.

Abu Nidal reportedly was in Egypt in August 1998, either under arrest or undergoing medical treatment. It is believed that he left within six months and moved to Baghdad in 1999. In February, Vice President Dick Cheney said Iraqi leader Saddam Hussein's regime "harbors terrorist groups, including Abu Nidal."

Abu Nidal's followers — working under a number of names, including the Fatah Revolutionary Council — are blamed for killing 300 people and wounding 650 in 20 countries since 1973, though U.S. officials say its activities had largely stopped in recent years.

Abu Nidal's death was reported Monday in the Palestinian daily Al Ayyam. In Baghdad, the deputy Palestinian ambassador, Nejah Abdul-Rahman, said he had no information regarding what he described as rumors of Abu Nidal's death.

Abu Nidal spokesman Ghanem Saleh, speaking in Lebanon, said he had only heard the report from news media and had no immediate comment.

Abu Nidal — the nom de guerre means "father of struggle" — was one of the key figures in Middle East terror for the past quarter century, but Israeli and U.S. officials said his activities had died down in recent years.

"In the last few years he lived in Baghdad with his men, it could possibly have been a one-man show," said Ephraim Inbar, an Israeli expert on terrorism at the Begin Sadat Center for Strategic Studies.

The Israeli Foreign Ministry refused comment on reports of his death, saying it was an internal Palestinian matter.

In 1982, Abu Nidal gunmen shot and critically wounded Israel's ambassador in London. Israel blamed Arafat's PLO and launched a huge invasion of Lebanon, driving Arafat and his forces out of the country.

Al-Banna was born in Jaffa when the area was part of British-governed Palestine. The family later moved to Nablus, and he left the area to organize opposition to the establishment of Israel.

The shadowy guerrilla masterminded the killings of both Jews and fellow Palestinians who opposed him. He flitted from one lair to another to avoid capture and switched backers from Iraq to Syria to Libya over the years. Officials accused him of running an international extortion racket running into millions of dollars, shaking down governments with threats of attacks, as well as dealing in arms and serving as a hit man for his various Arab backers.

In the West Bank city of Nablus, Abu Nidal's brother said Monday he had no information to indicate his brother had died in Baghdad — but added he had not heard from him in 38 years.

Mohammed al-Banna, a fruit and vegetable merchant, told Associated Press Television News that it was not the first time rumors have circulated concerning the death of his brother.