George Habash, founder of the Popular Front for the Liberation of Palestine (PFLP), died on today in Amman at the age of 82.
Mr Habash was hospitalised in Amman 10 days ago with heart problems and died shortly after 6pm Irish time.
Palestinian president Mahmud Abbas paid tribute to the 'historic leader' and ordered flags to be flown at half-mast for three days in the Palestinian territories in mourning for his death.
'The death of this historic leader is a great loss for the Palestinian cause and for the Palestinian people for whom he fought for 60 years,' Mr Abbas said in a statement.
Mr Habash stepped down as head of the Damascus-based PFLP in July 2000 after having led the faction which is a key component of the Palestine Liberation Organisation for more than 30 years.
He had been living in Jordan, the homeland of his wife, after an illness forced his retirement from political life.
The PFLP under Habash had hijacked airliners to Jordan and he called for the overthrow of Jordan's monarchy in 1970 before the Black September clashes in which the Jordanian army expelled the PLO from the kingdom.
Mr Habash was born in 1925 in the Palestinian town of Lydda, now in Israel and known as Lod, the son of a Greek Orthodox merchant family.