The army said the 21-year-old woman of Yazidi origin was rescued in a coordinated and complex operation this week that involved cooperation with the United States, Jordan and other international partners.

"She was recently rescued in a secret mission from the Gaza Strip through the Kerem Shalom crossing," the military said in a statement.

"Upon her entry into Israel, she continued to Jordan through the Allenby Bridge crossing and from there returned to her family in Iraq."

The Iraqi foreign ministry confirmed the woman's return, praising the cooperation between the United States and Jordan following more than four months of "efforts and follow-ups".

"The girl was handed over to her family this (Thursday) evening after returning to Iraq," the ministry said, without making any mention of Gaza or Israel.

In Washington, State Department spokesman Matthew Miller said the young woman was only 11 years old when she was "kidnapped by ISIS in Iraq, sold and forced to marry a Hamas fighter in Gaza, moved to Gaza against her will."

"The recent death of her captor in Gaza allowed her to escape, and we were contacted by the Iraqi government, who was made aware of the fact that she escaped, that she was alive, and that she wanted to come home to her family."

The United States "worked with a number of our partners in the region to get her out of Gaza, to get her safely home", Miller said.

Brigadier General Elad Goren of COGAT, the Israeli military body responsible for civil affairs in the Palestinian territories, did not provide specific details on how the women was moved from Iraq to Gaza but said it was most likely through the Rafah border crossing from Egypt.

"ISIS sold her to one person from Hamas, but she's been held by a group from Hamas," Goren alleged at a briefing, using another acronym for IS.

"(It's) further proof of the ideological links between Hamas and ISIS," he claimed.

Israeli officials have repeatedly tried to equate the Palestinian militant group which has ruled Gaza since 2007 with the jihadists of IS, whose extreme interpretation of Sunni Islam saw them target not only non-Muslim communities like Iraq's Yazidis, but also Shiite Muslims.

Goren said the woman was physically healthy "but not in a good mental situation", following the rescue operation.

"She wasn't hurt physically but we understand that the experience she had was terrible," he told reporters.

IS jihadists carried out horrific violence against the Yazidi minority as they rampaged across Iraq in 2014, killing men en masse and abducting thousands of girls and women.

The women were repeatedly raped and shared out among jihadist fighters as sex slaves in a reign of terror qualified as genocide by UN investigators.

After the massacres, some 100,000 Yazidis fled to Europe, the United States, Australia and Canada, according to the United Nations.

The Israeli military has been fighting against Hamas in Gaza since its unprecedented attack on Israel almost a year ago which resulted in the deaths of 1,205 people, according to an AFP tally.

Israel's retaliatory military offensive in Gaza has killed at least 41,788 people, the majority of them civilians, according to figures provided by the Hamas-run territory's health ministry.