Israeli and Qatari officials were set to meet in Norway on Saturday to revive talks about the release of hostages held in Gaza in return for a ceasefire and the freeing of Palestinian prisoners held by Israel, the Wall Street Journal reported on Saturday.

Qatari Prime Minister Mohammed bin Abdulrahman Al Thani was due to meet David Barnea, director of Israel’s Mossad intelligence agency, in Oslo, the report added, citing people familiar with the matter. Barnea is also likely to meet with Egyptian officials, the Journal reported.

Significant obstacles impede a resumption of negotiations on a new hostage deal including disagreements over the possible terms within Hamas, the report added, citing people familiar with the talks.

The report of the talks comes a day after Israeli military said it mistakenly killed three hostages being held in Gaza by Hamas.

The three Israeli hostages killed mistakenly in Gaza by Israeli forces had been holding up a white flag, according to an initial inquiry into the incident, a military official said on Saturday.

The incident happened in an area of intense combat where Hamas fighters operate in civilian attire and use deception tactics, the official said.

A soldier saw the hostages emerging tens of meters from Israeli forces in the area of Shejaiya, the official said.

“They’re all without shirts and they have a stick with a white cloth on it. The soldier feels threatened and opens fire. He declares that they’re terrorists, they (forces) open fire, two are killed immediately,” said the military official.

Read: UN demands ceasefire in Gaza as Israel, U.S. show increasing divisions

The third hostage was wounded and retreated into a nearby building where he called for help in Hebrew, the official said.

“Immediately the battalion commander issues a ceasefire order, but again there’s another burst of fire towards the third figure and he also dies,” said the official. “This was against our rules of engagement,” he added.

During a week-long truce in late November, Hamas released more than 100 women, children and foreigners it was holding in Gaza in exchange for the release of 240 women and teenagers.