Prime Minister Ariel Sharon reportedly twitched his eyelids and got teary after hearing his grandson's voice Monday, but doctors said it was too early to say whether they thought he was making progress after his devastating stroke.

Israeli police, meanwhile, released three Hamas politicians, including the No. 2 candidate in upcoming Palestinian elections, a day after detaining them.

In the West Bank city of Hebron, Israeli riot police clashed with Jewish settlers protesting plans to evict eight Israeli squatter families from an empty Palestinian market. Police began clearing out dozens of protesters from the settler enclave of Avraham Avinu, dragging some off rooftops. It was the fourth day of violence in Hebron, where about 500 Jewish settlers live among 170,000 Palestinians.

The officials at Hadassah Hospital said they could not confirm media reports that Sharon had briefly opened his eyes and appeared to recognize people around him.

The news came a day after the 77-year-old leader underwent a tracheotomy to help wean him off a respirator, though he remained in a coma and in "critical but stable" condition.

Outside experts have said the prime minister's failure to regain consciousness since his Jan. 4 stroke bodes poorly for his recovery prospects.

Hadassah Hospital issued a statement Monday saying relatives at Sharon's bedside reported "impression of eyelid movement whose significance is unclear."

The Web site of the Yediot Ahronot newspaper reported that Sharon opened his eyes twice Monday. Once, after a recording of a grandson's voice was played, the prime minister's eyes became teary, he blinked, then quickly opened his eyes, the site said. But they closed before doctors reached his room, the site added. The hospital said it couldn't confirm those reports.

Dr. Anthony Rudd, a stroke specialist at St. Thomas' Hospital in London, said eye movement — including opening — would not be "a dramatic breakthrough," though it would be more significant if it was in response to voice commands. Given the length of the coma, "one still needs to be pessimistic," he said.

Sharon's incapacitation jolted Israeli politics less than three months before Israeli elections.

Sharon's Kadima Party enjoyed a strong lead in opinion polls at the time of the stroke, and analysts warned the party might disintegrate without its founder and leader. But under acting Prime Minister Ehud Olmert, Sharon's top deputy, Kadima has strengthened its lead.

With Sharon unlikely to return, Kadima on Monday chose Olmert to stand in as party leader in the March 28 election. The decision put Olmert in a strong position to be Israel's next prime minister.

In one of Olmert's first major tests, he led his Cabinet in a unanimous decision Sunday to let Palestinians vote in Jerusalem in Jan. 25 parliamentary election, resolving a standoff with Palestinian leader Mahmoud Abbas.

Israel had threatened to ban voting if Hamas, which advocates Israel's destruction, ran in the election. Under the decision, the Cabinet said a ban on Hamas campaigning in the city would remain in effect.

Enforcing that ban, Israeli police rounded up three Hamas politicians on Sunday and held them overnight for questioning. Police also confiscated computers and documents in an office allegedly used by Hamas in east Jerusalem, said spokesman Mickey Rosenfeld. The charity office, which Israel suspects of being a Hamas front, followed an Israeli decision to ban the militant group from campaigning in the disputed city.

The candidates, including Mohammed Abu Teir, were released around midday Monday.

Abu Teir, Hamas' No. 2 candidate, called the detentions "unjust." He said he had just come out of prayers, and there were no plans to campaign. He also played down his connections to Hamas.

"They interrogated us on the basis that we are Hamas. We said 'No. we are Reform and Change,'" he said, referring to Hamas' main election slogan.

In Hebron, the settlers were battling the same forces who normally protect them in the tense city, police commander Avi Harush said. "We have a zero tolerance policy against people who use violence against police and soldiers and vandalize Palestinian property," Harush said.

Olmert condemned the violence. "There will be no forgiveness or compromises with this unacceptable behavior," he said.