TEL AVIV, Israel (AP) - Israelis carried gas masks to school and work Thursday after the opening U.S. attack on Iraq, while Palestinian children in the Gaza Strip waved pictures of Saddam Hussein and burned American flags.

In several areas hit by Iraqi Scud missiles during the 1991 Gulf War, school attendance was low. In the Tel Aviv suburb of Ramat Gan, one school reported about 20 percent attendance.

''I think he's (Saddam) is crazy enough to fire chemical weapons,'' said Shai Shtarker, 33, eating breakfast at a trendy Tel Aviv cafe. ''I think something big will happen.''

Israeli experts and officials continued to assure their people that the chances of an Iraqi attack against Israel in retaliation for the U.S.-led assault were small.

Prime Minister Ariel Sharon received a warning from the United States before it struck Iraq, Israeli government spokesman Maj. Gen. Amos Gilad said. U.S. officials said the air strikes targeted Saddam himself and other Iraqi leaders.

In the northern Gaza town of Beit Hanoun early Thursday, about 700 Palestinians, most of them schoolchildren, waved Iraqi flags and posters of Saddam and burned two U.S. flags.

They shouted ''Death to America, death to Bush!'' and ''We will sacrifice our soul and our blood for Saddam!''

The military on Wednesday instructed civilians to get their gas masks out, install their filters, and carry the masks with them at all times.

Several thousand Israelis in the Tel Aviv area, a target of Iraqi Scuds in 1991, were leaving for safer parts of the country, like Jerusalem, unlikely to be hit because of its holy sites, or Eilat, far out of range at Israel's southern tip.

However, a poll in the newspaper Yediot Ahronot showed that 84 percent of the Tel Aviv region's 2 million people did not plan to leave.

''We have buses blowing up, we have car accidents and compared to what we go through every day, this is nothing,'' said Gal Ganzberg, owner of beachside pub next to the U.S. Embassy in Tel Aviv.

During the first Gulf War, Iraq fired 39 Scud missiles at Israel, all with conventional warheads, causing damage but few casualties. The United States had the support of an Arab coalition back then. But this time, much of the Arab world is opposed to a war against Iraq.

About 2,400 families from the Tel Aviv area registered in the southern town of Kiryat Gat on Wednesday. Eight leading hotels in the Jerusalem area reported a surge of more than 1,500 calls from Tel Aviv residents looking for rooms.

British Airways and Germany's Lufthansa began canceling flights to Israel.

Travel agents reported an increase in reservations for flights out of Israel and advertised cut-rate deals. Some Israelis living abroad were returning to be with their families.

''War? We're ready - are you?'' read one travel advertisement in the Yediot newspaper. ''Special prices for packages in Israel and abroad, one-way and open tickets.''

Dotan Avraham, 73, from Tel Aviv, was heading to Jerusalem to wait out the war.

''I don't have the strength for war that I once had,'' Avraham said. Avraham was slated to check into the Jerusalem Gold Hotel, which changed its name to the George W. Bush Hotel to demonstrate solidarity with the president. A huge banner was placed outside.