Lebanon's pro-Syrian president came under mounting pressure to step down on Sunday after four generals close to him were arrested on murder charges over the killing of former Prime Minister Rafik al-Hariri.

A Lebanese magistrate issued formal arrest warrants on Saturday against the four pro-Syrian generals four days after they were detained on the recommendation of the chief U.N. investigator probing the February assassination.

The four men, charged with murder, attempted murder and carrying out a terrorist act, were close aides to President Emile Lahoud, especially Brigadier General Mustafa Hamdan, chief of the Republican Guard brigade in charge of his security.

Several politicians, allies and rivals alike, have urged Lahoud, a Maronite Christian, to quit. But two key Maronite leaders, Patriarch Nasrallah Sfeir and parliamentary opposition leader Michael Aoun, indicated they would wait until the investigation was completed and the evidence becomes clear.

"The fact that they were formally charged in martyr Hariri's assassination means that President Lahoud is convicted from a political if not judicial standpoint," Minister of Social Affairs Nayla Mouawad said. "He has to bow out."

EXTENDED TERM

The extension of Lahoud's term by three years exactly one year ago on the orders of Syria touched off a chain of events that included a U.N. resolution demanding Syrian forces to pull out of Lebanon, a number of assassinations and explosions.

Hariri's killing sparked anti-Syrian protests that forced Damascus to bow to international pressure to end its 29-year military presence in Lebanon in late April.

Many Lebanese blame Syria and its Lebanese allies for the killing, but Damascus denies any role.

Lahoud said last week he would stay in office for his full extended term.

Druze leader Walid Jumblatt, a bitter rival of Lahoud, told Al-Mustaqbal newspaper: "The security regime has fallen and the extension (of Lahoud's term) is finished. How costly this extension was."

Former Prime Minister Selim Hoss, once a close ally of Lahoud, hinted at what the president should do, calling on him to "take the step that safeguards Lebanon's national interests in the first place and the president's dignity in the second".

Several ministers belonging to the anti-Syrian majority in parliament said they would not be attending any cabinet meetings Lahoud attended in an attempt to isolate him.

Prime Minister Fouad Siniora said the cabinet would meet this week in his office. He did not say if he refuse to convene the government under Lahoud but added: "We have to take into consideration all that has happened recently."

Syria said on Saturday U.N. investigator Detlev Mehlis will visit Damascus on Sept. 10 to discuss interviewing Syrian officials.

The United Nations had complained Syria was not fully cooperating with the inquiry into the killing of Hariri along with 20 others in a huge bombing in Beirut.

Mehlis wants to question Syrian officials once responsible for security in Lebanon, which was controlled by its larger neighbour after the 1975-1990 civil war, but said on Thursday there were no Syrian suspects in the case so far.

PHOTO CAPTION

Chief of the Republican Guard Mustafa Hamdan (C) stands between Lebanese President Emile Lahoud (L) and former Prime Minister Rafik al-Hariri in Beirut in this undated file photo. (REUTERS)