The Islamic group Hamas has released six more hostages under a ceasefire agreement in the Gaza Strip.

The move on Saturday brought the total number of hostages freed by Hamas under the deal to 25. Israel has set free more than 1,100 prisoners in response.

The group handed over the remains of four other hostages on Thursday. But Israel said one body did not match the identity of the woman who Hamas said it was. It accused Hamas of "a violation of utmost severity."

Hamas later handed over another body, which was confirmed on Saturday to be that of the woman in question.

The group is scheduled to return the bodies of another four hostages next week, reaching the total of 33 hostages agreed to in the deal.

A six-week ceasefire between Israel and Hamas went into effect on January 19.

But negotiations for the next phase between Israel and Hamas have reportedly made little progress. The second stage should see a permanent end to the fighting and the release of the remaining hostages.