US Secretary of State Antony Blinken has arrived in Israel in his latest effort to push for a ceasefire and hostage-release deal in Gaza.

His ninth trip to the region since the war began in October comes days after the US presented a modified proposal aimed at bridging long-standing gaps between the two sides.

The US and Israel have expressed optimism about a deal since talks resumed in Doha last week, but Hamas says suggestions of progress are an “illusion”.

Differences are said to include whether Israeli troops will be required to withdraw fully from the Gaza Strip, as Hamas insists.

A Hamas source has told Saudi media that the proposals include the IDF maintaining a reduced presence along the Philadelphi Corridor, a narrow strip of land along Gaza’s southern border with Egypt.

But Israeli sources have told the Times of Israel that other procedures along the border could compensate for an Israeli withdrawal from the area in the first phase of the deal.

The Israeli military launched a campaign in Gaza to destroy Hamas in response to an unprecedented attack on southern Israel on 7 October, during which about 1,200 people were killed and 251 taken hostage.

More than 40,000 people have been killed in Gaza since then, according to the territory’s Hamas-run health ministry.

A ceasefire deal agreed in November saw Hamas release 105 of the hostages in return for a week-long ceasefire and the freeing of some 240 Palestinian prisoners in Israeli jails. Israel says 111 hostages are still being held, 39 of whom are presumed dead.

US President Joe Biden said earlier this week “we are closer than we have ever been” to a deal.

But previous optimism expressed during months of on-off talks has proven unfounded.

Israeli Prime Minister Benjamin Netanyahu told a cabinet meeting on Sunday that complex negotiations were taking place to secure the return of hostages, but some principles needed to be upheld for Israel’s security.

“There are things we can be flexible about, and there are things we cannot be flexible about, and we insist on them. We know very well how to differentiate between the two,” he said.

He also accused Hamas of being “obstinate” in negotiations and called for further pressure to be applied on the militant group.

A senior Hamas official told the BBC on Saturday: “What we have received from the mediators is very disappointing. There has been no progress”.

The original deal outlined by President Biden, based on Israel’s 27 May proposal, was to run in three phases:

• The first would include a “full and complete ceasefire” lasting six weeks, the withdrawal of Israeli forces from all populated areas of Gaza, and the exchange of some of the hostages – including women, the elderly and the sick or wounded – for Palestinian prisoners held in Israel.
• The second phase would involve the release of all other living hostages and a “permanent end to hostilities”.
• The third would see the start of a major reconstruction plan for Gaza and the return of dead hostages’ remains.

Meanwhile, the Hamas-run health authority in Gaza says Israeli air strikes killed at least 21 people including six children on Sunday.

The IDF said on Sunday it had destroyed rocket launchers used to hit Israel from the southern Gaza city of Khan Younis, the scene of intense fighting in recent weeks, and killed 20 Palestinians.