Prime Minister Ariel Sharon (searchurged his divided Cabinet on Sunday to approve a hotly debated prisoner swap with Hezbollah, even though it does not include Israel's most famous MIA, an air force navigator captured 17 years ago.

The vote in the 23-member Cabinet was seen as too close to call.

Sharon staked his prestige on the deal, one of the toughest tests of his leadership in nearly three years as prime minister. He lobbied hard among ministers, brushing aside criticism that the swap would be seen as rewarding terrorism.

"There is no reason to explain in words the importance of the decision the Cabinet must make today," Sharon said as the meeting got under way.

The swap would have Israel release more than 400 Palestinian and Lebanese prisoners in exchange for Israeli businessman Elhanan Tannenbaum (searchand the bodies of three soldiers held by the Lebanese guerrilla group. It does not address the fate of Ron Arad, an Israeli air force navigator shot down over Lebanon in 1986.

Arad's family has campaigned heavily against the deal. Arad is something of an icon in Israel, while Tannenbaum reportedly was lured abroad by Hezbollah (search) with a promise of a shady business deal to cover gambling debts.

Pressure on the ministers mounted further Sunday, with the airman's wife and daughter giving radio interviews just before the Cabinet convened.

Also, a participant in a secretive government probe into Arad's whereabouts said Sunday he believes the airman is still alive and held by Iran.

Critics of the deal say paying such a high price could be seen as rewarding terror and increase the motivation to kidnap Israelis, including civilians. The swap also could encourage Palestinian militants in the West Bank and Gaza to emulate Hezbollah's tactics.

While Arad is not part of the deal, Lebanese guerrilla leader Mustafa Dirani, who captured the airman and reportedly sold him to Iran in May 1988, is to go free. Dirani was kidnapped by Israeli commandos in 1994 as a bargaining chip for Arad.

Israel Radio quoted Sharon as telling the Cabinet ministers that leaving Tannenbaum in captivity would mean he will die.

Some 50 people in favor of the swap, including relatives of the three dead soldiers, marched outside the prime minister's office during the meeting.

Arad's daughter Yuval, who was 15 months old when her father was captured, told Israel Army Radio her family is giving up hope of ever seeing Arad.

"It is very embarrassing that I feel I have to convince people and the prime minister that they have to help me and help my father," she said.

"My mother says there is no chance. Apparently the years and the disappointments have taught her not to hold out hope," she said. "But I am still innocent. I still have a bit of hope that the Cabinet ministers will decide that my father is not less important than others and vote against the deal."

Sharon has said Dirani no longer has any value as a bargaining chip. But on Sunday, he said his proposal to the Cabinet would include a series of steps to be taken regarding Arad.

Meir Gilboa, a member of a committee that recently investigated Arad's disappearance, said the panel has seen documents indicating Arad is still alive and is being held in Iran.

Heading into the meeting, several ministers said they remained undecided.

"Sometimes there is a price that is forbidden to pay, and the country has to make difficult decision," said Diaspora Affairs Minister Natan Sharansky, a former political prisoner who spent nine years in a Soviet prison.

Aluf Benn, a commentator for the Haaretz daily, said Sharon was facing his toughest leadership test, "Sharon has taken a political risk and put his prestige and weight behind the controversial decision, which will pass with a small majority at best," he wrote.

Adding to the uncertainty, Hezbollah's leader said late Saturday that the exchange would collapse if a Lebanese militant jailed since 1979 for killing three Israelis is not freed.

Sheik Hassan Nasrallah, who heads the Lebanese militant group, said Samir Kantar, 41, must be part of the swap. On Friday, a senior Israeli government official said Kantar "has blood on his hands" and would not be included.