JERUSALEM, FEB. 20 -- Israeli soldiers today shot to death two Palestinians, one of them a 12-year-old boy, and wounded at least a dozen others as new violence erupted in several towns and villages in the occupied West Bank.

One of the most serious incidents occurred in the town of Ramallah. Dr. Isa Saltti, director of Ramallah Hospital, told reporters that soldiers fired tear gas and rubber bullets into the building, forcing patients to flee. He said at least one tear-gas canister landed in the hospital's maternity ward, which had already been evacuated by women with their babies after tear gas wafted through the area.

An Army spokesman could neither confirm nor deny Saltti's accusation, but said youths had initiated the violence at the hospital by throwing rocks from the roof of the building onto soldiers below.

One Palestinian was killed in Ramallah and a second, the 12-year-old, died in a shooting incident at the Tulkarm refugee camp that the Army said was under investigation.

Their deaths brought the toll of Arab fatalities since the uprising began on Dec. 9 to at least 57. Hundreds more have been wounded by gunshots and several thousand Palestinians have been injured by beatings administered under the Army's policy of using physical force instead of live ammunition against demonstrators.

The violence marked the end of several days of relative tranquility. Army officials attributed the new outbreak to today's warm, dry weather following a week of rain and to the upcoming visit to the Middle East of U.S. Secretary of State George P. Shultz. He is due to arrive here Thursday in pursuit of a new American peace initiative.

The Palestine Liberation Organization, outlawed by Israel, issued new leaflets today calling for a week of protests against Shultz's diplomatic mission, including marches, hunger strikes and, on Wednesday and Thursday, a general strike that would include all buses and taxis.

It called on residents to erect barricades and block traffic, take unspecified reprisals against alleged "collaborators" and defy military curfews. It urged local Palestinian leaders to boycott Shultz as they had done during a previous visit last September. A molotov cocktail was thrown at the office of the American consulate in predominantly Arab East Jerusalem today, damaging an awning. There were no injuries.

The trouble in Ramallah began this morning when hundreds of youths demonstrated in the central market area, the Army reported. A jeep of Border Police driving through a narrow alleyway was cut off by a makeshift roadblock, and youths began pelting the three occupants with rocks, bricks and bottles. An officer in the group cocked his gun to shoot in the air, the Army said, but was hit by a stone and fired as he fell, shooting a demonstrator in the head.

The demonstrator's body was taken to Ramallah Hospital and witnesses said soldiers tried to enter the hospital grounds to arrest alleged stone throwers. That set off another confrontation in which tear gas and rubber bullets were allegedly fired into the main building.

The shooting victim, a 19-year-old man from the nearby village of Kufr Nami, was buried this afternoon in an emotional ceremony in which hundreds of angry villagers participated. A second man was slightly wounded by gunfire, treated at the hospital and released, according to Saltti.

There were also shooting incidents at several other places, including the village of Bani Naim, near Hebron, where at least three persons were injured by gunfire. Witnesses said a crowd of several hundred demonstrators sealed off the main road and threw stones at soldiers. When the protesters moved toward Israeli positions, soldiers opened fire.

The Army also said soldiers and 200 Moslem worshipers clashed last night at the Tomb of the Patriarchs in Hebron, a site holy to both Moslems and Jews. Arabs spread prayer rugs on the floor and began to hold Friday prayers during Jewish services in an area normally used at different hours for worship by each of the groups. The Moslems refused to leave and were evicted by soldiers, the Army said. During the clash, one worshiper sought to strangle an Army officer, a spokesman said.

"I don't remember such a thing ever happening before," the spokesman said.