"I went through hell," says Yocheved Lifschitz, an 85-year-old grandmother and peace activist released by Hamas on Monday after two weeks in captivity.

Ms Lifschitz and her husband were kidnapped by Hamas gunmen on motorbikes and taken into a "spider's web" of tunnels underneath Gaza, she said.

She described being hit by sticks on the journey, but said most of the hostages were being "treated well".

She was freed alongside another woman, Nurit Cooper, 79, on Monday evening.

Extraordinary images show the grandmother shaking the hand of a Hamas gunman, just seconds before she was handed over to the International Red Cross at the Rafah crossing between Gaza and neighbouring Egypt.

"Shalom," she appears to say to the gunman - the Hebrew word for peace.

Ms Lifschitz was kidnapped, alongside her husband Oded, from Nir Oz Kibbutz in southern Israel on 7 October. He has not been released.

It was early in the morning when Hamas attacked their kibbutz, massacring the small community. One in four residents are believed to have been killed or kidnapped, including many children.

Speaking at a news conference from Ichilov hospital in Tel Aviv just a few hours after her release, Ms Lifschitz explained what happened after she was kidnapped.

She said she was hit with sticks during the journey into Gaza, and suffered bruises and breathing difficulties.

Her daughter, Sharone Lifschitz, who helped translate her mother's ordeal to reporters, said the 85-year-old was forced to walk for a few kilometres on wet ground.

Sharone said her mother was taken into "a huge network of tunnels underneath Gaza that looked like a spider's web".

Ms Lifschitz said she was among 25 hostages taken into the tunnels and after several hours, five people from her kibbutz, including herself, were taken into a separate room. There, they each had a guard and access to a paramedic and doctor.

She described clean conditions inside, with mattresses on the floor for them to sleep on. Another captive who was badly injured in a motorbike accident on the way into Gaza was treated for his injuries by a doctor.

"They made sure we wouldn't get sick, and we had a doctor with us every two or three days."

She also said they had access to medicines they needed and there were women there who knew about "feminine hygiene".

They ate the same food - pitta bread with cheese and cucumber - as the Hamas guards, her daughter Sharone added.

Asked by a reporter why she had shaken hands with the gunman, Ms Lifschitz said the hostage takers had treated her well and the remaining hostages were in good condition.

Sharone said she wasn't surprised by her mother's gesture - "the way she walked off and then came back and then said thank you was quite incredible to me. It's so her," she earlier told the BBC.

Hours before Ms Lifschitz and Nurit Cooper were released on Monday evening, the Israeli military held a screening for journalists showing raw footage recovered from Hamas body cameras, in an effort to remind the world of the brutality of the attack on Israel two weeks ago.

Among the clips was footage of Hamas gunmen cheering with apparent joy as they shot civilians on the road, and later stalking the pathways of kibbutzim and killing parents and children in their homes.

More than 1,400 people, mostly civilians, were killed in the attack.

Ms Lifschitz and her 83-year-old husband, Oded, are known peace activists who helped transport sick people out of Gaza to hospitals in Israel, according to their families.

Oded is a journalist who's worked for peace and the rights of Palestinians for decades, Sharone told the BBC.

According to the National Union of Journalists, he used to work for newspaper Al Hamishmar, and was among the first journalists to report on the massacre in two Palestinian refugee camps in Beirut in 1982.

"He speaks good Arabic so can communicate very well with the people there. He knows many people in Gaza. I want to think he's going to be OK," says Sharone.

In total, four hostages have now been released, after two American-Israelis, mother and daughter Judith and Natalie Raanan, were freed on Friday.

Israel says more than 200 people are still being held hostage. The husband of Nurit Cooper, who was also freed on Monday night, is believed to be among them.