Delays are already affecting the start of a four-day ceasefire deal between Israel and Hamas to let aid into Gaza and to free dozens of hostages, which was set to go into effect after nearly seven weeks of war.

The truce was due to commence on Thursday at 10 am (0800 GMT) but the exact timing remained unclear as Israel is yet to say when it would pause its air and ground offensive in the coastal area.

An Israeli army spokesman Daniel Hagari said the process of returning hostages from the Gaza Strip to Israel is complex and not yet concrete.

The military is preparing the implementation of this first phase of the hostage exchange agreement, said Hagari late on Wednesday.

However, the repatriation of the people kidnapped to the sealed-off coastal strip could take time and take place in several stages, he said.

“The release (of hostages) will begin according to the original agreement between the parties, and not before Friday,” Israel’s security adviser Tzachi Hanegbi was quoted by the Times of Israel as saying.

“The talks on the release of our hostages are progressing and will continue on an ongoing basis,” he said.

The first exchange of hostages kidnapped in Israel for Palestinian prisoners was initially expected to take place on Thursday.

The Times of Israel cited an Israeli official as explaining the delay by saying that both Israel and Hamas would have to sign a document ratifying the agreement for it to come into force.