JERUSALEM, JAN. 17 -- Israel exuded relief and euphoria this morning as the U.S.-led alliance launched its air war against Iraq and appeared to successfully preempt the missile strike with which Iraqi President Saddam Hussein repeatedly threatened the Jewish state.

Official sources said Israeli intelligence had detected no movement this morning at military bases in western Iraq, designated by the United States as H-2 and H-3, following air strikes on them during the night. Intermediate-range missiles capable of reaching targets inside Israel were deployed at the two bases. The sources said that while it was not yet certain that the Iraqi missile threat had been entirely eliminated, the chances were now good that Israel would not be drawn into the Persian Gulf war.

"I can assure Israelis it will be a peaceful day," said Yossi Olmert, the director of the Government Press Office. "If the present situation continues, we will not be part of this conflict."

Gen. Yaacov Lapidot, an advisor to Defense Minister Moshe Arens on domestic defense measures, struck a more cautious note. Lapidot pointed out that Iraq might still have mobile missile launchers available for use and that some of its planes, stored in concrete bunkers, might have survived this morning's strike. "There exists a possibility" that Iraq will still try an attack on Israel and "a few {planes} could get through or a missile or two," Lapidot said.

Military authorities continued to impose emergency civil defense measures through Thursday this morning, telling Israelis to stay in their homes and keep their army-issued gas masks nearby in case of an attack.

All 1.7 million Palestinians in the occupied West Bank and Gaza Strip were placed under curfew, and the army warned Arabs that anyone leaving their his home "does so at his own risk."

Arens announced on radio and television this morning that while the U.S.-led air attack "seems to have been effective, it's too early to say at this time that the danger to Israel has passed." Still, he conceded with a grin, "It is a very good morning."

Other government officials were elated over the apparent early success of the allied raids. "It's too good to be true," said a Foreign Ministry official, "though we in Israel have seen this before -- in 1967," when a lightning Israeli strike destroyed Arab air forces at the onset of the Six Day War.

Former prime minister Yitzhak Rabin, who was Israel's chief of staff during the Six Day War, told Israeli radio that the country owed a debt of gratitude to the United States for the air strike, which, he said, "will be taught as a lesson in the annals of military history."

Ezer Weizman, the commander of the 1967 Israeli air victory, said Israel "tips itshat to the United States."

As a long night of tension gave way to a crisp, sunny day, cities around Israel were deserted as citizens obeyed the government's call to remain indoors. But the silence, broken by the occasional roar of Israeli air force interceptors keeping watch overhead, was utterly different from the eerie quiet that gripped the country Wednesday as it waited anxiously for war.

After staying up most of the night listening to the radio, clutching their gas masks and jamming telephone lines with calls to friends and relatives, many Israelis today were almost giddy with relief. "I guess everyone is happy, because it looks successful and not too many people seem to have been killed," said Pnina Beck, a Jersualem schoolteacher who waited at home this morning with her husband and three children.

Still, few took the risk of going outside except for the 200,000 civil defense personnel and other employees in vital services called out today. Early this morning isolated workers and soldiers in uniform waited in ones and twos on street corners and bus stops, hitching rides from passing cars. For the majority indoors, Israeli television filled the time with hours of continuous news broadcasts, including liberal borrowings from CNN and other U.S. networks.

In perhaps the last installment of a dispute that has entertained secular Israelis throughout the crisis, a group of Orthodox rabbis today decreed that devout men were allowed to shave their long beards so that, if it becomes necessary to use gas masks, they will fit snugly. The rabbis also announced that the devout should stay at home with their worldly civil defense gear rather than going out to synagogues to pray.

Authorities reported disturbances by Palestinians in two East Jerusalem neighborhoods early today, and placed them under curfew.

However, the outburst of unrest by Iraq's many supporters in the occupied lands, predicted by both Israeli and Palestinian spokesmen, had not materialized by midday.

Israeli radio reported that mosques in the West Bank and Gaza broadcast news of the war together with cries of "Allahu Akhbar"("God is great"), but the army curfew appeared to have inhibited demonstrations.

Apart from the suppression of any Iraqi offensive, the allied air strike appeared likely to have achieved Israel's key aim during the Persian Gulf crisis: the destruction of Iraq's chemical and nuclear arms potential, officials said.

Prime Minister Yitzhak Shamir's government strongly pressed Washington for such a move against the Iraqi arsensal, insisting that without its elimination there could be hope for stability in the Middle East.

Reports that U.S. and allied planes and missiles had struck 50 or more strategic targets inside Kuwait and Iraq overnight left government officials beaming this morning. "We feel very satisfied," said Olmert. "As a fighting force, Iraq has been strategically defeated."