JERUSALEM, NOV. 13 -- Israeli authorities arrested three prominent Palestinian leaders today and ordered them imprisoned without trial in the most severe measure taken against the local Palestinian leadership in more than a year.

Military authorities said they had detained journalists Radwan Abu Ayyash and Ziad Abu Zayyad, two of the best-known Palestinian spokesmen in the West Bank. The two frequently have been accused by Israel of being leaders of the intifada, as the Arab uprising in the Israeli-occupied territories is called.

Defense Minister Moshe Arens ordered both held for six months of "administrative detention," meaning they will be imprisoned without trial in a desert camp maintained by Israel for Arab militants.

In addition, authorities said a Palestinian leader in the Gaza Strip, Ahmed Yaziji, had been arrested and ordered to serve a year in detention. Yaziji, a physician, was earlier dismissed by the army from his post at a Gaza City hospital.

The action by the government of Prime Minister Yitzhak Shamir appeared tailored to satisfy hard-liners in the governing coalition who have been demanding a crackdown on the Arab rebellion, which is nearing the end of its third year. It came amid a new wave of Israeli-Palestinian violence over the last month, and two days before the second anniversary of the Palestinians' declaration of statehood in the occupied lands.

The move appeared likely to create new diplomatic difficulties for Israel just as it tries to extricate itself from a confrontation with the Bush administration and U.N. Security Council. "Admittedly it's a problem," a senior official said. "The timing is not good from a political point of view."

Israel's diplomatic problems and the pressure from the domestic right wing stem from the Temple Mount incident on Oct. 8, in which police clashed with Moslem demonstrators near Jerusalem's holiest sites and killed at least 17 Arabs. Since then there has been a rash of revenge attacks by Arabs in Israel and the occupied territories and from neighboring Jordan, and militant Israeli Jews have responded with assaults on Arabs.

In what some saw as a further concession to the right, police confirmed today that one of the commanders criticized after the Temple Mount incident, Jerusalem commander Aryeh Bibi, had been promoted.

Bibi was blamed by an Israeli investigative commission for failing to take steps that could have prevented the violence. His post was abolished in a police reorganization this week but officials confirmed today that he had been promoted to full inspector general and made chief of personnel at national headquarters.

Early today, an Israeli soldier was killed by an Arab infiltrator from Jordan in the second clash between the army and armed intruders on the border inside a week. Later, two police were stabbed and lightly wounded by an Arab in the Moslem quarter of Jerusalem's Old City, and a militant Israeli follower of the slain Rabbi Meir Kahane was arrested when found carrying a submachine gun near the Western Wall.

The detentions of Abu Ayyash and Abu Zayyad were the most important to be carried out against senior Palestinian leaders since August 1988, when the army ordered administrative detention for Faisal Husseini, the most prominent Palestinian leader in Jerusalem. Abu Ayyash, head of the Arab Journalists Association, served six months in detention immediately after the intifada began in December 1987.

Military officials charged that Abu Ayyash and Abu Zayyad were West Bank leaders of the Fatah faction of the Palestine Liberation Organization and were coordinating the escalation of the rebellion. Authorities said the two had helped write leaflets of the uprising's underground Unified Command, had served as conduits for PLO funds sent from abroad to the territories and had helped direct the uprising's "strike forces."

However, under the procedures of administrative detention, the army is not required to disclose any specific evidence, and officials briefing journalists tonight refused to detail any of the charges. The Palestinians have the right to appeal their detention to a military panel, and ultimately to the Supreme Court.

Palestinians said the detentions showed that Shamir's government had fallen captive to its most extreme elements. "The far right seems to be setting the agenda of the Israeli government these days," said Daoud Kuttab, a prominent Palestinian journalist.