Negotiators are in the Egyptian capital Cairo for a new attempt to end fighting in Gaza in exchange for the release of hostages, the latest in a series of fraught attempts to strike a deal between Israel and Hamas.

The heightened tensions between Israel and Iran have created a new sense of urgency to end the 10-month war. Iran has threatened retaliation against Israel since a series of figures in Iranian-backed militant groups were killed in a period of weeks, including the assassination of Hamas political leader Ismail Haniyeh in Tehran.

Iran-backed militant group Hezbollah said last night it had carried out the first phase of its retaliation for the killing of a top commander, but the strikes had no impact on the talks.

Here’s what we know:

What’s going on? Hamas representatives arrived in the Egyptian capital on Saturday evening, where negotiators from Israel, the US, Egypt and Qatar held talks. The delegation will hear from mediators on the latest developments in the deal talks, Izzat al-Rishq, a member of Hamas’ political bureau, said in a statement on Saturday. Israeli negotiators are also present.

What’s on the table?: A three-phase peace plan was first outlined by US President Joe Biden in May, which includes the release of hostages coupled with a “full and complete ceasefire”. The White House has been pushing to get the deal done and has previously maintained that it has been accepted by Israel, but Israeli Prime Minister Benjamin Netanyahu says fundamental problems remain.

What are the main bottlenecks? Significant differences remain between the two sides. Israel has made it clear that after the first six-week phase, a halt in fighting can only be that and it is not prepared to agree to a permanent ceasefire. Hamas has indicated that it is unhappy with the latest proposal, as it did not include a permanent ceasefire and introduced new conditions for the exchange of prisoners. Another major sticking point is the future of the Philadelphia corridor in southern Gaza. Israel has demanded that it retain control of the border area, while Hamas has said that Israeli troops must withdraw from the area.

Is a deal likely? The US is optimistic about the final phase of the negotiations. Biden said last week, “We are closer than ever.” But the talks have been going on for months and it remains the case that there are major differences to overcome. Haniyeh has played a crucial role for Hamas in the talks, while Netanyahu is under competing pressure from hostage families to make a deal and from his cabinet to defeat Hamas.