The death of a hunger-striking Palestinian prisoner in a maximum security facility in the Negev desert touched off angry Arab demonstrations today and demands that the prison be closed on humanitarian grounds.

The prisoner, who had been force-fed along with most of the 75 inmates at the Nafha Prison, died of pneumonia after being transferred to a hospital ward at Ramle Prison near Tel Aviv, authorities said.

The Interior Ministry appointed a committee to investigate the death of the inmate, Mohammed Shahada Jaafri, who had been serving a life sentence on a conviction of infiltrating from Jordan in 1968 and murdering a man.

Two other Arab prisoners among 26 transferred to Ramle were also hospitalized with pneumonia, but prison officials refused to say whether their illnesses were connected to the forced feeding through tubes inserted in the mouth and nose.

A lawyer representing five of the inmates, Lea Tsemel, charged that her clients had been beaten by guards and forced to drink salt water.

Jaafri's death sparked demonstrations by Israeli human rights activists and inmate's families at the British Consulate and the International Red Cross in East Jerusalem today.Protesters carried signs saying: "Close the Nafha liquidation camp."

Yesterday, about 40 demonstrators staged a sit-in at the U.S. Consulate in East Jerusalem, prompting complaints by Israeli Foreign Ministry officials that the U.S. consular officials had aided an anti-Israel demonstration.

A spokeman for the consulate said that the protesters arrived unexpectedly and that they were allowed inside the courtyard because of the danger of heavy traffic in a narrow street outside.

Nafha Prison is located near Mitzpe Ramon in the middle of Negev, and the families of several inmates charged today that conditions in the over-crowded cells are "barbaric." Temperatures in the desert are over 100 degrees, and the prison, opened last May to house troublemakers from other facilities, has little ventilation, the families charged.

Anwar Hussebeh, former Jordanian defense minister and an East Jerusalem lawyer, said at a news conference today that a person on a hunger strike for 10 days was not likely to die of pneumonia. He said Jaafri may have died as a result of fluids entering his lungs while undergoing forced feeding.

Another lawyer, Felicia Langer, said she visited Nafha on Friday and found eight to 10 inmates crowded into each 30-square-foot cell and locked up 23 hours a day.

David Zilberman, spokesman for the prison services, confirmed that the inmates are not given beds and that they eat their meals in the cells. But he said the prison is well-ventilated and not as overcrowded as other prisons in Israel housing Jewish inmates.

Earlier this month, prison services commissioner Haim Levy declared that the conditions in Israeli prisons are "catastrophic" and are deteriorating quickly. Half of the 6,000 inmates in Israeli prisons are serving time for security-related offenses.

Of the Nafha Prison, Zilberman said, "Maybe it's not so nice, but the situation is better than in other prisons."

So far, prison authorities have refused to allow reporters to visit Nafha, citing security reasons.