Israeli Prime Minister Benjamin Netanyahu has said he does not rule out further strikes on Hamas leaders "wherever they are", as the heads of Arab and Islamic states held a summit to back Qatar after Israel's attack last week in the Gulf state.

The September 9 strike targeting leaders of the Palestinian militant group in Doha was a significant escalation of Israeli military action in a region shaken by conflict since the Hamas-led October 7, 2023, attacks that ignited the Gaza war.

While the assembled Arab and Muslim leaders were expressing solidarity with Qatar, US Secretary of State Marco Rubio met Netanyahu and gave strong backing for Israel's hardline stance, although Washington has expressed unease over the Qatar strike.

Speaking alongside Netanyahu in Israel, Rubio said the only way to end the war in Gaza would be for Hamas fighters to free all hostages and surrender. While the US wants a diplomatic end to the war, "we have to be prepared for the possibility that's not going to happen," he said.

Rubio will travel to Doha on Tuesday, the State Department said, to "reaffirm America's full support" for the Gulf state's sovereignty - words he did not use in front of Netanyahu.

Trump told reporters in Washington that Netanyahu "won't be hitting in Qatar" again, and said he wasn't informed by Netanyahu about Israel's attack.

Hamas has said the Israeli strike killed five of its members, including a son of its exiled Gaza chief, but its leadership survived. Qatar says one of its security agents also died.

Qatari Emir Sheikh Tamim bin Hamad Al-Thani urged the summit to take "practical and decisive steps" in response to the "cowardly and treacherous" strike, saying it occurred as Hamas leaders were studying a US ceasefire proposal.

The Arab League and Organisation of Islamic Cooperation joint session, which brought together nearly 60 countries, also called for a review of ties with Israel after the strike.

A joint statement from the summit urged "all States to take all possible legal and effective measures to prevent Israel from continuing its actions against the Palestinian people", including "reviewing diplomatic and economic relations with it, and initiating legal proceedings against it".

The statement also urged member states to "coordinate efforts aimed at suspending Israel's membership in the United Nations".

Crown Prince Mohammed bin Salman, Saudi Arabia's de facto ruler, was among those present on Monday, as were Iranian President Masoud Pezeshkian, Iraqi Prime Minister Mohammed Shia al-Sudani, Turkish President Recep Tayyip Erdogan and Palestinian president Mahmud Abbas.

"Tomorrow, it could be the turn of any Arab or Islamic capital," said Pezeshkian, whose country fought a 12-day war with Israel in June, at one point attacking a US base in Qatar in retaliation for strikes on its nuclear facilities.

"The choice is clear. We must unite."

President Abdelfattah al-Sisi of Egypt, the first Arab country to recognise Israel, warned its attack in Qatar "places obstacles in the way of any opportunities for new peace agreements and even aborts the existing peace agreements with countries in the region".

Turkish President Recep Tayyip Erdogan accused Israel of adopting a "terrorist mentality". (Agencies)