RAMALLAH, West Bank — Palestinian President Yasser Arafat fears he's next on Israel's hit list after the assassination Monday of Hamas founder Sheik Ahmed Yassin, aides said. Israeli security officials say their focus is on Hamas - for now.

The missile strike that killed Yassin may have shaken Arafat in more ways than one. The killing sparked huge demonstrations throughout the West Bank and Gaza, showing just how formidable a rival Hamas has become to Arafat's Palestinian Authority.

Some 15,000 Palestinians expressed their condolences at a wake arranged by Hamas in Ramallah. A similar event hosted by Arafat at his nearby headquarters drew only about 1,500 people, many of them Palestinian Authority officials.

After Yassin's killing, Arafat expressed concern he, too, might be targeted. "Arafat feels he is threatened, and we feel he's threatened because when they target Sheik Yassin, they are not far from Arafat," said Palestinian Communications Minister Azzam Ahmed.

Another cabinet member, Saeb Erekat, said Arafat's safety was discussed during an emergency cabinet meeting Monday. "Of course there is concern," he said. "This might be the end of the game, destroying the Palestinian Authority and killing President Arafat."

Roni Daniel, military correspondent for Israel's Channel Two TV, cited a senior Israeli defence official as saying Arafat could be a target soon.

However, a security official told The Associated Press that Israel's campaign would focus on Hamas. The official said strikes were expected to intensify.

During three and a half years of fighting, Israel has killed dozens of militants in targeted operations, but Yassin was by far the most senior Palestinian to be assassinated.

Israeli Prime Minister Ariel Sharon has accused Arafat of supporting terrorism. Sharon called him "irrelevant" and last September threatened to "remove" the Palestinian leader.

Arafat has not left his West Bank headquarters in nearly two years, although Israel has shown no sign it plans to attack him.

Monday's assassination sparked calls in some Israeli quarters to go after Arafat. "I hope that the government will go on to wipe out every terrorist leader, including Yasser Arafat," said Shaul Yaalom, a legislator from the ultra-nationalist National Religious Party.

Arafat condemned the air strike and declared three days of mourning for Yassin. During the cabinet meeting, he also led a Muslim prayer for the dead.

Analysts suggested Arafat was caught off guard by the mass protests in the streets. At one point Monday, about 2,000 enraged protesters, some of them firing rifles into the air, gathered outside Arafat's headquarters, banging on the walls and demanding to speak to him.

Yassin was Arafat's main political foe, and Arafat was always careful not to confront the Hamas leader openly. But Yassin's death could make Hamas an even more formidable rival, said Israeli analyst Yossi Alpher.

"My sense is that Hamas gets a boost in the public eye on the Palestinian street. That's not good for Arafat's standing," he said.

Hamas rejects the existence of Israel and is viewed by many Palestinians as a less corrupt alternative to the Palestinian Authority.