Israeli tanks and bulldozers shelled buildings and exchanged fire with Palestinian gunmen in the West Bank towns of Jenin and Jericho early Thursday, killing three Palestinians and wounding at least 21 others.

The Israeli army said the latest incursions into Palestinian territory, which lasted several hours, were intended to "root out terror." Palestinians accused the government of Prime Minister Ariel Sharon of exploiting the world's preoccupation with terror attacks in the United States to escalate its military strikes.

Amid the tensions, Secretary of State Colin Powell called Sharon and Palestinian leader Yasser Arafat late Wednesday.

Arafat agreed to a Powell request that he meet as soon as possible with Israeli Foreign Minister Shimon Peres. Meanwhile, Peres said there was tentative agreement on a meeting for truce talks, but details were not yet finalized.

The Israeli actions in Jenin and Jericho began in the early hours of Thursday and the forces pulled out several hours later, in line with previous Israeli incursions.

In Jenin, Israeli forces destroyed the rest of a police compound they attacked the day before, and then withdrew, the army said.

Palestinians said the tanks shelled houses and fired machine guns, killing three people -- a man and woman in a house and a gunman. Nine other people were wounded during the Jenin incursion, they said.

In the desert oasis of Jericho, flares lit up the night sky as tanks rolled into town. Residents said several greenhouses were destroyed and at least one house was damaged by tank fire. The local hospital reported 12 people wounded.

A cloud of smoke and an orange glow could be seen at the Aqbat Jaber refugee camp area at the south end of the town, near the Oasis Casino, a main Jericho attraction that was closed at the beginning of the Palestinian-Israeli fighting a year ago.

Israeli Defense Ministry spokesman Yarden Vatikay said the military had information that Palestinian militants in Jericho were preparing attacks against Israelis, but gave no details.

He noted that on Sunday, two Israelis were killed in a shooting ambush several miles north of the town.

Palestinian Cabinet minister Saeb Erekat, who lives in Jericho, said Israel lacked any reason to enter the town. He drew a connection between the incursions and the terror attacks in New York and Washington Tuesday that destroyed the World Trade Center and damaged the Pentagon.

"The Israelis are using the tragedy of the events in New York and Washington, feeling that the attention of the world is elsewhere," he said. "There was nothing to provoke this."

Gissin said the Jericho operation was planned and approved before Tuesday's attacks in the United States, as a response to the shooting of Israelis in the area.

Also Thursday, Israel destroyed Palestinian positions in the West Bank towns of Qalqiliya and Salfit. The army said the attacks came in response to a Palestinian shooting ambush late Wednesday in which an Israeli woman was killed.

Israel, meanwhile, started easing restrictions adopted after the attacks in the United States, gradually opening its air space, said Pini Schiff, Ports Authority spokesman.

He said planes would be cleared for landing from 22 foreign airports in the first stage. Most of the airports were in Europe, but they also include Cairo, Egypt and Amman, Jordan.

However, Israel's land border crossings would remain closed until further notice, he said.

The limitations scuttled Arafat's long-awaited trip to Syria to mend fences after two decades of strained relations. Arafat was to have met Wednesday in Damascus with Syrian President Bashar Assad.

Israel did not give Arafat permission to fly from Gaza to Egypt, and he was unable to make the trip by land, Palestinian officials said.

European Union foreign policy chief Javier Solana, who has led EU efforts to bring Peres and Arafat together, said he hoped the two would meet soon despite the world's focus on the U.S. terror attacks.

"I hope very much that even with this disaster, the meeting everybody has been working on in the Middle East will continue," Solana told reporters Thursday.