Thousands of Jordanians marched on Parliament in Amman on Tuesday, demanding that the government break off relations with Israel.

AMMAN, Jordan, April 2 — Thousands of Jordanians braved a frigid downpour to march on Parliament today, demanding that the kingdom sever ties with Israel, while protesters in Egypt packed the streets around Cairo University for a fifth straight day.

Up to now the anger in the streets has not gone beyond the control of any of the autocratic governments in the region. But officials spend each day and much of the night monitoring television reports or checking their mobile phones for the urgent headlines flashed there by subscription services.

They dread the moment when a major death toll — or worse, news of the demise or exile of the Palestinian leader, Yasir Arafat — will put moderate Arab governments squarely on a collision course with their explosive, aggrieved populations.

"It's a volatile situation open to all possibilities," said Adnan Abu-Odeh, formerly a royal political adviser here and an ambassador to the United Nations. "The only truth is that people are angry and frustrated. So far the demonstrations have not been destabilizing, but nobody knows what will happen in the next 24 hours."

The circumstances of Mr. Arafat's encirclement in Ramallah, with Israeli soldiers stationed right outside his door, make senior officials especially edgy.

Despite Israeli pledges not to harm him, there is widespread concern that he might suffer some fatal accident. "The first casualty is the peace process," said Marwan Muashar, Jordan's foreign minister, urging Washington to press for an unconditional Israeli withdrawal from the compound. "This is a regional problem. They are putting their Arab friends at risk in the region."

The governments of Egypt and Jordan are counted among the most vulnerable. They have repeatedly tried to explain their peace treaties and full diplomatic relations with Israel as a means of exerting positive pressure on the fate of the Palestinian cause. But skepticism over such arguments is running high.

"The Arab regimes look more impotent than they ever have," Mr. Abu-Odeh said. "Their legitimacy has been reduced enormously. There is an implied test: if you say relations are rewarded, show me how useful they are. People want proof that the government's good relations with America and Israel are meaningful in that they will help both end the siege on the Palestinian people and Arafat."

Up to now the Bush administration has shown scant sign of being ready to meet such demands. Indeed, the president has made clear that he regards the Israeli operation in the West Bank as broadly justified, and he has focused his demands on Mr. Arafat, insisting that he renounce terror, clearly and in Arabic.

Cabinet ministers here said dozens of protests flare up daily throughout the country, with 38 counted on Friday alone.

The Amman march today was the largest in the capital since Israel activated its intense assault on the West Bank on Friday. The protest included a huge contingent from the Muslim Brotherhood flaunting a picture of Osama bin Laden and chanting in favor of attacking Israel.

"The army of Muhammad will return," they intoned. "The army of Muhammad is at the border."

Senior officials and political analysts said governments in the area needed to take some measure to assuage the anger and frustration on Arab streets. Egypt and Jordan have conferred on whether to downgrade relations with Israel by expelling its ambassadors.

"The demonstrations are getting stronger by the day," Mr. Muashar said. "The street is literally boiling." He said the continuing Israeli assault, combined with Washington's approval, was forcing moderate Arab governments to distance themselves from the United States.

"We are being forced to take steps we don't want to take," he said, "because people are angry and public opinion in the Arab world cannot be ignored."

Mr. Muashar was particularly critical of Washington for suggesting in the midst of an Israeli assault, with tanks besieging his compound, that Mr. Arafat should somehow be reining in Palestinian extremists.

"The leader is under siege and cut off from the outside world, and there are demands that he do more to stop the violence," Mr. Muashar said. "It is ludicrous."

After five days of resisting public pressure for a legal demonstration, the Jordanian government finally acceded to the request by opposition parties to march. But they tried to take the sting out of it by dispatching a few ministers to take part.

Marchers in the crowd of about 6,000 who walked through the city blocking traffic for three hours were scathing in their criticism of Jordan's links to Washington and its peace treaty with Israel.

"The Jordanian government should throw out the American ambassador even before the Israeli, because it is only America who can pressure Israel to stop this aggression," said Wadha Rajoub. Like many demonstrators, she said she had turned out in part because she had family in the West Bank. Her cousin Jibril Rajoub, the West Bank security chief for the Palestinian Authority, is also under siege.

She was horrified by television pictures of the Palestinian dead in Ramallah being buried in a mass grave on hospital grounds because the morgue there had run out of room and Israel had barred their transportation elsewhere.

Protesters poured scorn on the official government line that it should not break ties with Israel because it could still influence the Sharon government to ease the measures against the Palestinians.

"Reality shows that you cannot trust the Israelis nor influence them," said Omar Hudhud, one of dozens of attorneys from the Lawyers Syndicate marching, many of them in their professional robes.

Officials in Jordan and Egypt have emphasized that they will not break ties with Israel, despite the demands of their populations. But those outside the government here speculated how long they could stick to that pledge, especially as demonstrations increase in magnitude daily.

Hasan Abu-Nimah, a former Jordanian ambassador to the United Nations, suggested that Washington should realize that its long-term interests did not lie in letting the Sharon administration pulverize the Palestinian Authority.

"To encourage Sharon, or to provide cover for what he is doing, is bad for Israel," he said. "Destroying Palestinian society is only going to create more suicide bombers."

The Arab League announced a special meeting of its foreign ministers in Cairo on Wednesday to consider what action might be taken. Iraq announced that it would press its proposal to revive the 1973 Arab oil embargo — a plan highly unlikely to be enacted, given the state of the economy among exporters.

Some members want countries bordering Israel to open their borders to allow volunteer fighters to cross. Col. Muammar el-Qaddafi, the Libyan leader, made such a similar suggestion a day earlier, mocking the Arabs by saying their arms would be more useful sold as scrap and remade into cooking pots.

But with no countries in the area ready to go to war with Israel, it is virtually certain that the suggestion will be rejected.

Officials in Jordan noted that it had recently reinstated its checkpoints along the Jordan valley after a team sent by Hezbollah in Lebanon had tried to cross into Israel.

Thousands of demonstrators in Cairo trying to march from Cairo University to the nearby apartment building housing the Israeli Embassy were again turned back with water cannons and tear gas.

In a separate protest at the Egyptian Foreign Ministry, crowds of artists, intellectuals and union leaders — who have long opposed relations with Israel — urged the government to expel its ambassador and sever ties with the "Zionist enemy."

In Tunis, the Tunisian capital, police in riot gear, brandishing tear gas and truncheons, battled to keep several thousand students within the campus of the national engineering school, where they were chanting things like "Anger! Anger! No more summits, no more words!"