JERUSALEM — Israel said Wednesday that it would release 20 Palestinian women from its jails in exchange for a videotape of a captured Israeli soldier that would prove that he was alive. The soldier, Gilad Shalit, was seized by the Islamic group Hamas and other Palestinian militant groups in 2006 in a cross-border raid and taken into Gaza.

The prisoner release offer, announced Wednesday by the office of Prime Minister Benjamin Netanyahu, was the first significant sign of progress in negotiations about him since Mr. Netanyahu took office in March.

Israeli and Palestinian officials said the exchange was expected to take place on Friday.

“Israel will receive updated and unequivocal proof of Gilad Shalit’s well-being and status,” Mr. Netanyahu’s office said in a statement, describing the deal as a result of an Egyptian initiative meant to build confidence before the “decisive stages of negotiation” for the release of the soldier, who has been promoted to staff sergeant from corporal during his captivity. The prime minister’s office added that the negotiations were “still expected to be long and arduous.”

In Gaza, Mahmoud Zahar, a senior Hamas official, said the deal was “small and symbolic” but could pave the way to a more comprehensive agreement.

“We are offering a report explaining the situation of the soldier in return for the release of 20 women prisoners,” he said as he entered a Red Cross office in Gaza City on Wednesday.

According to a list issued by Israeli prison officials, the women to be freed were all due to finish their terms within two years, meaning that they were not convicted of serious offenses or were in any way close to release.

Mr. Zahar said the prisoners included four from Hamas; five from Fatah, the rival mainstream Palestinian group; three from the more extremist Islamic Jihad; and one from the leftist Popular Front for the Liberation of Palestine. He said the others were not affiliated with any group. Only one of the women is from Gaza; the rest are from the West Bank.

Hamas has demanded the freedom of 1,000 Palestinian security prisoners from Israeli jails in return for Sergeant Shalit’s release. Many prisoners on the Hamas list have been convicted of deadly terrorist attacks.

Ehud Olmert, the prime minister when Sergeant Shalit was seized, had been under intense public pressure to resolve the issue before the end of his term, but negotiations via Egyptian mediators failed to produce his release.

Israeli officials said at the time that Israel had agreed to release some 325 prisoners from a list of 450 demanded by Hamas in the first stage of a deal. Israel also insisted that some of those released would go into exile.

Mr. Netanyahu appointed a new chief negotiator, and the Egyptian mediation efforts were supplemented by German mediation.

Sergeant Shalit, now 23, was last seen publicly being dragged alive into Gaza in 2006. A year later, Hamas released an audiotape of the soldier believed to be authentic. His family has also received at least two letters written in what family members said was his handwriting.

A video would be the first sign he was alive since Israel’s three-week military offensive in Gaza, which ended in mid-January.

The Israeli president, Shimon Peres, said the deal announced Wednesday was a “positive step” in the negotiations. But he added, “The road to his release is still long and not simple, and we do not want to create any illusions.”