Yemen's Iran-backed Huthi rebels said Israeli air strikes on Thursday killed nine people, after the group fired a missile toward Israel, badly damaging a school.

Israeli Prime Minister Benjamin Netanyahu threatened further retaliation.

The Huthis, who control most of Yemen's population centres, have repeatedly launched missiles at Israel since the Gaza war broke out more than a year ago.

Israel has previously hit back against targets in Yemen, but Thursday's were the first against the rebel-held capital Sanaa.

US Secretary of State Antony Blinken called Wednesday on Syria's triumphant HTS rebels to follow through on promises of inclusion, saying it can learn a lesson from the isolation of Afghanistan's Taliban.

The Islamist movement rooted in Al-Qaeda and supported by Turkey has promised to protect minorities since its lightning offensive toppled strongman Bashar al-Assad this month following years of stalemate.

US Secretary of State Antony Blinken said Wednesday he remained hopeful of reaching a ceasefire between Israel and Hamas in Gaza and promised to use his remaining month in office to achieve it.

Blinken, however, declined to predict success after repeated disappointments in his government's efforts to end 14 months of brutal war in the Palestinian territory.

"Look, I'm hopeful. You have to be. We're going to use every minute of every day of every week that we have left to try to get this done," said Blinken, who leaves office on January 20.

US Secretary of State Antony Blinken said Wednesday that President-elect Donald Trump had a window to negotiate with Iran, saying the development of a nuclear weapon by Tehran was not inevitable.

The outgoing top US diplomat acknowledged that the cleric-run state may be more seriously considering a nuclear weapon after military setbacks in the region.

In the last year, Israel's military has hit Iranian air defenses and weakened its Lebanese ally Hezbollah, while rebels have toppled its main Arab ally in Syria, Bashar al-Assad.

Turkey on Wednesday rejected US President-elect Donald Trump's claim that the rebel ouster of Syrian strongman Bashar al-Assad was an "unfriendly takeover" by Ankara.

"We wouldn't call it a takeover, because it would be a grave mistake to present what's been happening in Syria" in those terms, Foreign Minister Hakan Fidan told broadcaster Al Jazeera in an interview.

"For Syrian people, it is not a takeover. I think if there is any takeover, it's the will of the Syrian people which is taking over now."

Efforts to strike a Gaza truce and hostage release deal between Israel and Hamas have repeatedly failed over key stumbling blocks, but recent negotiations have raised hope of an agreement.

On Tuesday, Washington expressed "cautious optimism" on the possibility of an "imminent deal".

This comes following reported indirect negotiations in Qatar, mediated by the gas-rich Gulf state along with Egypt and the United States.

Why the sudden optimism?

Visiting UN humanitarian chief Tom Fletcher called Wednesday for a massive aid boost for Syria to respond to "this moment of hope" after the ouster of longtime strongman Bashar al-Assad.

"Across the country, the needs are huge. Seven in 10 people are needing support right now," Fletcher told AFP in a telephone interview as he visited Syria.

"I want to scale up massively international support, but that now depends on donors. The Syria fund has been historically, shamefully underfunded and now there is this opportunity," he said.

A Syria war monitor said 21 pro-Turkey fighters were killed Wednesday after they attacked a Kurdish-held position near a flashpoint northern town despite a US-brokered ceasefire extension in the area.

The fighting between Turkish-backed factions and US-backed Kurdish-led forces comes more than a week after Islamist-led rebels toppled Syria's longtime strongman Bashar al-Assad.

Visiting UN humanitarian chief Tom Fletcher called Wednesday for a massive aid boost for Syria to respond to "this moment of hope" after the ouster of longtime strongman Bashar al-Assad.

"Across the country, the needs are huge. Seven in 10 people are needing support right now," Fletcher told AFP in a telephone interview as he visited Syria.

"I want to scale up massively international support, but that now depends on donors. The Syria fund has been historically, shamefully underfunded and now there is this opportunity," he said.

At the end of a winding road on a dusty hillside in the Israeli-annexed Golan, the yellow gates of Trump Heights slowly open for cars, passing a golden-lettered sign honouring the US president-elect.

Emblazoned with Israeli and US flags, the settlement is an homage to Donald Trump who in 2019 recognised Israel's sovereignty over the strategic plateau, making the United States the first, and so far only, country to do so.