Lebanese Prime Minister Omar Karami and his government resigned Monday amid unprecedented pressure and mass protests demanding it take responsibility for the assassination of his predecessor.

The surprise decision was announced by Karami in a brief statement to a parliamentary session debating Rafiq Hariri's killing.

"Out of concern that the government does not pose an obstacle to the country's welfare, I announce the resignation of the government I had the honor to lead," an emotional Karami told parliament.

Karami said he had never coveted an official post and could no longer tolerate the injustice done to him.

Parliament Speaker Nabih Berri was stunned by the move as Karami insisted on the resignation though his government had enough votes to win a confidence motion.

Lauding Hariri as an "icon for the Lebanese," Karami also urged a fair probe into the Feb. 14 car bombing which killed Hariri and 17 others in Beirut.

The government resignation drew enormous cheers from some 20,000 demonstrators who gathered at the Martyrs' Square in the heart of Beirut, brandishing Lebanese national flags and chanting anti-Syria slogans.

Opposition groups, which accuse Syria of being behind Hariri's death, called for protests to continue until Syria, a major power broker in Lebanon, withdraws its 14,000 troops from its tiny neighbor.

"Syria out!" "Freedom, sovereignty, independence," the crowd shouted.

Hundreds of soldiers and policemen blocked off the square while protest leaders urged their followers not to provoke the security forces, who refrained from trying to disperse the peaceful crowd.

Many spent Sunday night at the square despite a ban on demonstrations announced by Interior Minister Suleiman Frangieh.

"The battle is long and this is the first step. This is the battle for freedom, sovereignty and independence," said opposition MP Ghattas Khouri.

On the drastic developments, Syria adopted an aloof attitude. "This is an internal affair," a Syrian official said, while expressing hope it would help end the current crisis in Lebanon.

According to pan-Arab Al Arabiya TV channel, Lebanese President Emile Lahoud, a Damascus favorite, has accepted the resignation but asked the premier to stay on as a caretaker.

Washington was watching the situation "with great interest".

"The resignation of the Karami government represents an opportunity for the Lebanese people to have a new government that is truly representative of their country's diversity," White House spokesman Scott McClellan told a news brief.

"The new government will have the responsibility of implementing free and fair elections that the Lebanese people have clearly demonstrated they desire," McClellan added.

US Assistant Deputy Secretary of State David Satterfield, currently in Beirut, reiterated on Monday his country's demand for an immediate Syrian withdrawal from Lebanon.

Expressing the US dissatisfaction with the Lebanese and Syrian conduct, Satterfield said "both countries should be aware that the world has changed and could no longer tolerate their behavior."

On the other side, Damascus has pledged to redeploy its troops to eastern Lebanon, closer to the border, but indicated it would be linked to peace with Israel and therefore not imminent.

(Xinhua News Agency March 1, 2005)