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In a surprise deal announced Wednesday, Hamas will give Israel a videotape providing a first glimpse of a captured Israeli soldier to prove he is alive in return for the release of 20 Palestinian women held in Israeli prisons.

It marked the first tangible sign of progress in more than three years of talks aimed at a larger prisoner exchange, and it could lead to an end to a crippling blockade of the impoverished, war-torn Gaza Strip, which is ruled by militant Islamic Hamas.

Israel said the video-for-prisoners exchange would take place Friday.

Up to now, the only signs of life from the soldier, Gilad Schalit, were several letters and an apparently carefully scripted audio tape, released just months after he was captured in June 2006. Hamas-linked militants tunneled under the Gaza-Israel border, attacked an Israeli army base from the rear, killed two soldiers and hauled a bleeding Schalit off into captivity.

LIVESHOTS: Proof of Life on Missing IDF Soldier

Hamas is demanding the release of as many as 1,000 Palestinian prisoners in exchange for the soldier, including many convicted of deadly attacks against Israelis. Israel says it will not ease the blockade until the soldier is freed.

Hamas and Israel are bitter enemies who do not talk directly to each other, so Egypt, joined recently by Germany, has been mediating in on-again, off-again contacts.

The first sign of progress came Wednesday when Israeli Prime Minister Benjamin Netanyahu's office released a statement disclosing the deal — a recent videotape of the soldier in exchange for freedom for 20 Palestinian women prisoners.

The statement described it as a "confidence-building measure."

In Gaza, Hamas spokesman Osama Muzini confirmed the deal, which he said was struck after German mediators asked for information on Schalit's health, and Hamas responded that "nothing is free."

"Twenty prisoners will be released in exchange for the Zionist enemy's learning about his life through a cassette that shows him and reassures the enemy that he is still alive," Muzini said.

A Hamas Web site reported that the videotape was about one minute long. Israeli officials said it would include proof that it was taken recently. They did not elaborate.

Commenting on the deal, Israel's ceremonial president, Shimon Peres, called it "a positive step in the negotiations, but the road to (the soldier's) release is still long."

Such a deal could be critical for the 1.4 million residents of Gaza who are mired in poverty and facing shortages of vital supplies because of the punishing blockade, imposed after Hamas overran the territory in 2007 and expelled forces loyal to Western-backed Palestinian President Mahmoud Abbas.

The shortages have prevented Hamas from repairing the massive damage caused in Gaza by an Israeli military offensive last winter, aimed at stopping daily rocket fire.

On Wednesday, Israeli warplanes attacked three smuggling tunnels between Egypt and Gaza — the main lifeline into the blockaded territory — in retaliation for rocket attacks over the past several days, the military said.

The captured soldier's long plight has become a festering sore in Israel, with large, tearful rallies on his birthdays and frequent media appearances by his father. Reflecting wide support for the cause, one Israeli TV anchor ends his daily newscast by mournfully reciting how many days the soldier has been held captive.

Lately, however, Israeli opponents of such a deal have been speaking out, warning that releasing top Palestinian militants could result in the deaths of many Israelis in renewed attacks — as has happened after previous exchanges.

Earlier this month, Defense Minister Ehud Barak told a group of high school students to "stop whining" when they challenged him about the Schalit case. Barak then said soldiers must realize that "fulfilling their missions requires a willingness to risk their lives."

Barak endured a storm of criticism for his blunt remarks, but some praised his attitude, crediting his military record. A famed commando who rose to become military chief of staff, Barak, 67, is Israel's most-decorated soldier.

Also Wednesday, a 17-year-old Palestinian was run over and killed by an Israeli army jeep in the northern West Bank village of Yabad.

The military said as Palestinians threw rocks at an Israeli army patrol, a jeep "experienced mechanical difficulties" and accidentally hit the youth.