A pickup truck packed with 330 pounds of TNT exploded in a crowded market Saturday, killing 52 people and wounding 125 others in one of the deadliest bombings in Lebanon since the 1983 suicide attack on the U.S. Marine headquarters in west Beirut.

The truck bomb exploded as morning shoppers filled the ancient Bab Al Tabbaneh open market in the heart of the city at 9 a.m., demolishing a small hotel, destroying at least 10 shops and about 30 cars and igniting a series of fires, police and witnesses said.Shortly after the explosion, the market was littered with bodies, charred cars and shards of glass. The injured screamed for help as black smoke from the fires billowed into the air.

"It's a real massacre," Prime Minister Selim Al Hoss said in a statement. "It was carried out by butchers."

No one immediately claimed responsibility for the attack, but rival factions in Lebanon blamed everyone from Israel to Syrian agents.

Police and hospital sources in the port city of Tripoli, 42 miles north of the capital, said the blast killed 52 people and wounded 125. Authorities said the blast apparently had no other target than the crowd of morning shoppers.

Police sources said an initial investigation indicated the site of the explosion was not near the homes of any local political figures or Syrian military installations.

Syria has provided security for the predominantly Sunni Moslem city of 500,000 people since 1976, when Damascus sent 30,000 soldiers to Lebanon to end the civil war. Police sources said the blast dealt a severe blow to the Syrian security role in the city.

It was the seventh car bomb attack in Tripoli since the beginning of 1985 and the worst in the city since an explosion June 19, 1985, killed 52 people and wounded 100.

The bomb was one of the deadliest in Lebanon since the Oct. 23, 1983, attack on the U.S. Marine headquarters in Moslem west Beirut. In that attack, a suicide driver raced a vehicle packed with explosives into the building and detonated the bomb, killing 214 Americans and wounding scores of others.

The force of Saturday's explosion blew out windows as far as 150 yards away. The facade of a nearby hotel crumbled, and many inside were believed to be among the dead.

Rescue workers and firefighters rushed to the scene of the blast as Syrian and Lebanese troops fired their automatic rifles into the air to disperse hundreds of curious onlookers so the emergency vehicle could get through.

The rescuers took at least 40 bodies to the nearby Islamic Hospital. Dozens of shocked women, some of them relatives of the dead, wailed and cried at the entrance of the hospital and beat their cheeks and chests.

Some of the dead were wrapped in large sacks and taken by their relatives for burial. Youths touring the streets in cars pleaded for people to donate blood.

Rival factions in Lebanon blamed the attack on a wide variety of different forces.

Nabih Berri, chief of the pro-Syrian Shiite Amal militia, charged that "Israeli hands" were behind the explosion.

The Voice of Free Lebanon, run by the anti-Syrian Christian militia, quoted a statement by the shadowy February 9th organization charging that Syrian agents planted the bomb.

The February 9th group, which had claimed responsibility for a series of attacks on Syrian positions in Tripoli, is thought to be comprised of extremist anti-Syrian Sunni Moslem activists.

An official of the Christian Lebanese Forces militia said the attack was an "indication that a new round of violence would strike Lebanon again."