The Israeli Army's northern commander testified today that he and other Israeli officers privately feared that mass killing of civilians would result from the decision to send Lebanese Christian Phalangist militia units into the Palestinian refugee camps of West Beirut.

Testifying before the three-member judicial board of inquiry investigating Israel's role in the massacre last month, Maj. Gen. Amir Drori said that one officer, whom he identified only as "Reuven," warned of a possible massacre on Sept. 16, the night the Phalangist units entered the Sabra and Shatila refugee camps.

"Everyone, somewhere in his mind, conceived of such a possibility," Drori acknowledged under questioning, in testimony that conflicted with earlier statements by Israeli Defense Minister Ariel Sharon.

The commission also made public earlier testimony by an Israeli tank commander who said that, from an embankment outside one of the camps, he saw Lebanese Phalangist troops kill five people, including a pregnant woman. When one of his men asked the Phalangists later why they had done it, the tank commander said, a Phalangist said that "pregnant women will give birth to terrorists."

The tank commander, Lt. Avi Grabovsky, testified that other Israeli soldiers told him they had informed superiors about the killings and had been told not to intervene.

The testimony by Drori, the senior Israeli field commander in Lebanon at the time, is sharply at odds with repeated public assertions by Sharon that no Israeli official thought it possible that there would be a Phalangist rampage against Palestinian civilians.

Sharon told the commission on Oct. 25 that he had anticipated civilian casualties when he authorized the Phalangist forces to enter the camps, but nowhere near the 700 to 800 deaths that Israeli intelligence estimated occurred between Thursday night, Sept. 16, and Saturday morning, Sept. 18, when the Phalangists left.

"No one foresaw -- nor could have foreseen -- the atrocities committed in the neighborhoods of Sabra and Shatila," Sharon told the commission.

Asked whether there had been any apprehension before the operation about possible acts of vengeance or slaughter, Sharon told the commission, "No, no," but he added that "we have a great deal of experience in fighting in built-up areas," and "anyone who thinks" that in fighting in built-up areas "no civilians would be killed then he is mistaken. . . . We know that civilians get killed."

Speaking in a low, sometimes almost inaudible voice, Drori testified for almost two hours in the second public session the commission has held since the investigation began. A pool of Hebrew-speaking reporters provided a translation of Drori's testimony.

It was clear from today's session and the earlier public questioning of Sharon that the commission is zeroing in on two points: whether the Israelis anticipated, or should have anticipated, the possibility of a massacre, and why they did not act sooner than they did to halt the slaughter.

Drori testified today that he ordered a halt to Phalangist operations inside the refugee camps late Friday morning, Sept. 17, while allowing the militia units to remain in the area. He said he did this based on a "bad feeling" conveyed to him by the Israeli divisional commander in Beirut, identified only as "Amos."

Pressed by the commission members for the reason for this order, Drori insisted he had no concrete evidence of a massacre at the time. "All I had were suspicions," he said. His doubts, he said, were based on fragmentary reports, including one that in conducting house-to-house searches in the refugee neighborhoods the militiamen were "shooting into buildings as they entered."

After issuing the order, Drori said, he telephoned Israeli Army Chief of Staff Lt. Gen. Rafael Eitan, telling him, "I think that perhaps the Phalangists overdid it."

The order that Drori said he issued Friday morning is the earliest indication yet of high-level Israeli concern over what was happening inside the camps, and leaves open the question of when other, more senior officials also learned of a possible massacre. Sharon has testified that he learned of widespread civilian casualties Friday night, about 10 hours after his ranking field commander in Lebanon ordered a halt to the Phalangist operation.

It also remained unclear why Eitan and Drori, in a meeting with Phalangist commanders on Friday afternoon, agreed to allow the militia units to remain in the Palestinian neighborhoods until the next morning. Asked today whether there was not some urgency in removing the Phalangist units from the camps, Drori replied, "No. They said they needed until Saturday morning, and we gave them that."

While Drori said that on that Friday morning he had no specific information about a massacre, the testimony of Grabovsky that the commission late today made public in an English-language excerpt indicated the kind of information that was available to Israeli commanders at that time.

Grabovsky testified before the commission Thursday. He said that on the Friday morning that Drori issued his order for the Phalangists to halt, he had been stationed just outside Shatila.

"I saw them Phalangist militiamen taking out two men, at about 8 or 9 in the morning," Grabovsky said. "They kicked and slapped them -- one of them got a rifle butt in his head. They brought them back into the camp. After a while we heard several shots, and we saw two Phalangists coming out. I didn't understand anything.

"Afterwards, I took the tank up onto the embankment," he continued. "When I stood on the embankment I saw how they took a group of five civilians and killed them. The group was women and children; I don't know the ages. . . . They stood in the destroyed house. Two men, it seems to me, took part in this killing. It was in the morning, before noon."

Grabovsky said his tank crew told him that Israeli regimental headquarters had already been informed that civilians were being killed. According to Grabovsky, "the regimental commander told them the soldiers who reported the killing : we know, it's not to our liking, and not to intervene."

Later, Grabovsky said, one of his men asked a Phalangist soldier why they were killing civilians. "He answered that pregnant women will give birth to terrorists, and that children when they grow up will be terrorists. While we talked, a tractor driven by a Phalangist went by. He said it was to destroy and cover up the bodies."

A tractor also figured in Drori's testimony. He said the Phalangist units requested a tractor to clear roads and bunkers and were given one after all Israeli markings were removed from it.

Throughout his testimony Drori suggested, perhaps unintentionally, his own suspicions about the Christian militia units. He said that at one meeting with Phalangist commanders before they entered the camps he warned them that they "should behave like human beings, that they should not hurt nonfighters, women, children, old people."

At a later meeting, Drori testified, he urged a regular Lebanese Army officer to send his own troops into the camps, warning that "you can guess how they the Phalangists will act" toward the Palestinians.

Asked by commission member Judge Aharon Barak whether he used the word "disaster" during this conversation, Drori said, "I can't remember. I may have used the word because I was trying to pressure him to go into the camps."

After his public appearance, Drori was also questioned by the commission in a closed session. The commission is to hold another public hearing Monday to hear testimony from doctors and a nurse who were in a nearby hospital during the massacre.