The September 9 strike targeting leaders of the Palestinian militant group in Doha marked 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.
Washington has said it was not warned in advance before Israel attacked Qatar, which houses the biggest US military base in the Middle East. President Donald Trump said on Sunday Israel had to be "very, very careful".
"They have to do something about Hamas, but Qatar has been a great ally to the United States," Trump said.
Hamas has said the Israeli strike on Qatar 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, addressing the emergency summit, urged "practical and decisive steps" in response to the "cowardly and treacherous" Israeli strike. He said the attack occurred as Hamas leaders were studying a US ceasefire proposal.
With a broad spectrum of states attending - including Iran, Turkey and Saudi Arabia - it wasn't immediately clear what measures might be agreed at the summit. A statement was expected to say that the Israeli attack and other "hostile acts" threaten coexistence and efforts to normalise ties in the region, according to a draft seen by Reuters.
President Masoud Pezeshkian of Iran, which backs Hamas and fought a 12-day war with Israel in June, said "no Arab or Islamic country is safe from the attacks of the Zionist regime (Israel) and we have no choice but to unite our ranks".
President Abdel Fattah al-Sisi of Egypt, a US ally which signed a peace treaty with Israel in 1979, said Israel's actions "put obstacles in the way of any opportunities for any new peace agreements and even aborts existing ones".
Rubio will travel to Qatar after his visit to Israel. He called on Qatar to continue to play a constructive role in resolving the Gaza conflict, saying it could help reach the goals of releasing all 48 hostages still held in Gaza, disarming Hamas and building a better future for Gazans.
But his words alongside Netanyahu suggested Washington now considers a diplomatic solution unlikely and is backing Israel's plan for a major new military operation that Netanyahu says will crush Hamas once and for all.
"As much as we may wish that there be a peaceful, diplomatic way to end it, and we'll continue to explore and be dedicated to it, we also have to be prepared for the possibility that's not going to happen," said Rubio, calling Hamas "savage terrorists".
"Hamas needs to cease to exist as an armed element that can threaten the peace and security of the region," he said.
With Rubio at his side, Netanyahu did not rule out annexing the Israeli-occupied West Bank in response to moves by some countries to recognise a Palestinian state at the UN General Assembly later this month. France and Britain are among the countries that have said they will do so.
Asked if Israel was considering extending its sovereignty to the West Bank, Netanyahu said: "A future step is a future step. We don't need to expose it ahead of time".
"It's clear that taking unilateral actions against us simply invites unilateral actions on our part," he said.
