GAZA CITY, DEC. 28 -- The wheels of military justice ground swiftly today in Army Judge Moshe Shefi's courtroom in the military compound on As Siraya Street here.

The 16 Palestinian defendants, dressed in blue prison garb and accused of participating in the violence that wracked the occupied Gaza Strip and West Bank for two weeks, came in eight at a time. As the military prosecutor intoned the charges in Hebrew, a soldier translated them into Arabic. All but one defendant pleaded guilty -- some after complaining that they had been beaten by soldiers.

There were no witnesses other than the defendants and no defense lawyers -- they were on strike, protesting the way the trials are being run. Most of the cases took about 10 minutes to complete, some less than three.

But there seemed to be two kinds of military justice being meted out today. In Nablus on the West Bank, 35 of 37 defendants pleaded not guilty and had their cases postponed. All had lawyers and Judge Yehoshua Halevy criticized the Army's preparation of the cases, calling the whole procedure "a mess."

In reaction to the trials, informed sources said, U.S. Ambassador Thomas Pickering told Israeli Defense Minister Yitzhak Rabin today that the United States plans to send diplomatic observers to some of the military hearings.

Saying that Washington remains concerned about possible human rights violations in the cases stemming from the rioting, Pickering said a Hebrew-speaking diplomat from the U.S. Embassy in Tel Aviv and an Arabic-speaking diplomat from the U.S. Consulate in Jerusalem will jointly observe some of the trial proceedings, the sources said.

Some of the defendants in Judge Shefi's courtroom today said they had been beaten up by soldiers while in detention, but none could identify by name his alleged assailants. The judge, in military uniform, took note of their injuries -- one man had a badly bruised right arm in a sling, another a swollen shoulder, another bruises on his back and legs -- but he ruled valid their signed confessions.

Sentences were uniform. Those convicted of throwing stones at soldiers drew three months in prison and $650 fines; those convicted of simply participating in an illegal demonstration were given 20-day sentences and $200 fines.

"When I see a trial like this, you can just do whatever you want," said Said Ahmed Kaffefi, as he changed his plea from not guilty to guilty after watching his fellow defendants plead. Like them, he got 20 days and a $200 fine.

So it went throughout the day as Israel's military court system shifted into high gear to cope with trying the more than 900 Palestinians arrested during the security crackdown that finally helped shut off the civil violence in which 21 Palestinians were shot dead.

"Justice will be done, and quickly," Brig. Gen. Amnon Strasnov, the Army's chief prosecutor, told a television interviewer. "One does not contradict the other. . . . Every defendant will enjoy all the rights allowed a defendant in court during the normal course of procedures."

But Judge Halevy, in Nablus, complained to the Army that files were missing and witnesses were not ready. The number of postponements there means a backlog that military officials concede will defeat their goal of swift sentences for the maximum deterrent effect.

Not so in Gaza, where the courts moved with assembly-line dispatch. Of 57 Palestinians brought before the courts, 46 pleaded guilty and received sentences ranging from 20 days to three months, the Army said. There were no lawyers present and family members held a vigil outside the compound because most were not allowed inside although many seats were empty.

The differences in part reflected the fact that the Gaza lawyers stayed on strike while West Bank lawyers decided to defend their clients. But it also reflects differences in the profiles of the two regions and in the personalities of their Israeli military commanders.

The 580,000 Gazans are part of the Third World: impoverished, isolated from the rest of the Arab world, increasingly fundamentalist in religious orientation and poorly educated. The 850,000 Arabs of the West Bank are generally better trained, more sophisticated and more affluent. They stand more on their rights, lawyers there say, and are less intimidated by Israeli courts and military authorities.

In dealing with his volatile region, Gaza commander Gen. Yitzhak Mordechai seems less inclined to legalisms and public relations, military officials say, while the West Bank commander, Maj. Gen. Amram Mitzna, is more image-conscious and careful. Mitzna, for instance, pledged yesterday that Palestinian prisoners in the West Bank were receiving humane treatment and not being held in tents, while Mordechai has been publicly silent on the matter.

Shefi's court is a dilapidated room with peeling paint and makeshift benches. An Israeli flag was draped on the wall behind him. Heaters hummed in the background while a bored-looking clerk took notes. The translator kept an Uzi sub-machine gun by his chair and the prosecutor packed a handgun. Police and soldiers outnumbered defendants.

The Gazans brought to court today, most them in their early to mid-20s, generally looked dazed and passive. There was little of the defiance and restless energy that marked the crowds that challenged armed Israeli soldiers with stones and molotov cocktails two weeks ago. Some looked close to tears as they stood before the judge.

Kaffefi was an exception. He was accused of taking part in a demonstration in which youths shouted nationalistic slogans and carried the flag of the outlawed Palestine Liberation Organization -- a crime in this country, which considers the PLO a terrorist movement.

He denied the charges and shouted over the prosecutor that he had been taken from his home late at night, dragged off to detention, kept without food for three days and beaten. "I want to show you my wounds," he told the judge in perfect Hebrew, lifting his shirt and turning his back to display bruises.

"Who did that?" asked Shefi. "I don't know," was the reply. "I was blindfolded. All of them beat me."

"Okay, okay," said the judge. He ordered the case postponed and told the prosecutor to find witnesses for a trial. But as Kaffefi saw other defendants plead guilty and get off with 20 days and $200, plus four months suspended and five years of probation, he changed his mind.

"If you're confessing just to finish this case and not because you're guilty, we won't accept it," said the judge.

"I saw people demonstrating and I walked alongside them -- what else do you want from me?" pleaded Kaffefi. "When I get out of prison, if there are ever problems again, I'm going to Egypt or Jordan."

He too received 20 days and $200, and sat down with a smirk. Even the judge smiled.

Other cases were less amusing. Mahmoud Kamal, 34, the oldest of the group, was charged with directing youths to erect a barricade of rocks and garbage pail lids on the road outside his house.

First he said he didn't do it, then, when confronted with a written confession, he said he did. He pleaded for mercy, saying he had been trained as a teacher but could only get a job as a day laborer tarring roads in Israel. The judge gave him a month in jail and a $550 fine.

The second shift of eight went more quickly as noon grew near. It took the judge 10 minutes to find Sammy Said guilty and sentence him to two months and $650 for throwing stones.

Talat Daabis, 17, took only two minutes to get a similar sentence. He looked too stunned to talk but nodded his guilty plea. His mother, one of a handful of relatives allowed to watch, stood up and pleaded with the judge, saying she was a poor widow and Daabis the sole means of support for her and her four children. The judge said he could pay the fine in installments.

Only Yusef Hammad, 18, his arm in a sling, insisted he was not guilty and that his signed confession had been wrung from him after he was beaten. Shefi postponed his case indefinitely.

Israeli military officials say Palestinian defendants have the right to a lawyer but that there is no legal requirement that they be given one.

"We will not stop conducting trials just because attorneys do not want to appear," said Strasnov.

An Army spokesman said the military would appoint Israeli defense lawyers for Palestinians in serious felony cases.

Fayez Abu Rahme, a Gazan lawyer who heads the lawyer's council that decided on this week's strike, says the defendants would likely have received the same sentences even with attorneys.

"It's meaningless for us to be there because whatever we say is not heard," said Abu Rahme, who has appeared for 15 years before the military courts. "These courts are not good and we had to show our dissatisfaction somehow."