Heading to Qatar from Israel, which overnight carried out major new strikes in Gaza, Rubio was pessimistic about a ceasefire deal but said Qatar uniquely could help.

"We're going to ask Qatar to continue to do what they've done, and we appreciate very much, and that is, play a constructive role in trying to bring this to an end," Rubio told reporters as he flew out of Tel Aviv's Ben Gurion airport.

"Obviously they have to decide if they want to do that after last week or not, but we want them to know that if there's any country in the world that could help end this through a negotiation it's Qatar," he said.

Rubio said the United States would work with Qatar to finalise a defence agreement soon despite the Israeli military action.

President Donald Trump told reporters in Washington that Prime Minister Benjamin Netanyahu "won't be hitting" Qatar again.

Rubio made no such comments in Israel. Speaking next to Netanyahu, Rubio was reticent on praising Qatar, saying only that it was important to look forward after the strike.

In language also not used publicly in Israel, State Department spokesman Tommy Pigott said that Rubio in Doha "will reaffirm America's full support for Qatar's security and sovereignty following Israel's strike".

The State Department said Rubio would meet Qatar's emir, Sheikh Tamim bin Hamad Al Thani.

Qatar has been at the centre of diplomacy to broker an end to the nearly two-year Gaza war, and Israel struck as Hamas leaders were gathering to discuss a new US ceasefire proposal.

Rubio backed Israel's new offensive on Gaza City and its stated goal of eradicating Hamas, casting doubt on whether a diplomatic solution was on the cards.

Following his meetings with Netanyahu, Israel launched a heavy overnight bombardment of Gaza City, witnesses told AFP on Tuesday.

- Duelling US relationships -

Qatar is home to the largest US air base in the Middle East and is the forward base of Central Command, the US military command responsible for the region.

The tiny energy-rich monarchy is classified by Washington as a major non-NATO ally, and has assiduously courted Trump, including gifting him a luxury airplane.

But few countries are closer to the United States than Israel, which has enjoyed robust support from Washington despite international opprobrium over its military campaign in Gaza.

Hamas triggered the war with an unprecedented October 7, 2023 attack on Israel.

Netanyahu said his government assumes "full responsibility" for the attack on Doha "because we believe that terrorists should not be given a haven and the people who planned the worst massacre of the Jewish people since the Holocaust cannot have immunity".

He compared the strike to how the American military acted "very boldly" after the September 11, 2001 attacks on the United States, with its war on Al-Qaeda in Afghanistan and the 2011 raid into Pakistan that killed attack mastermind Osama bin Laden.

Before the October 7 attack, Israel and the United States had reportedly quietly encouraged Doha's role, including its transfer of millions of dollars to Hamas in hopes of maintaining stability in Gaza.

In 2012, Qatar agreed to host the Hamas political bureau with US blessing.

Both the United States and Israel viewed Qatar, with its close relationship with Washington, as a better place to keep an eye on Hamas and prevent the militants from basing themselves in Iran, whose clerical state openly backs the group.

Rubio will visit Doha a day after Arab and Islamic leaders meeting in Qatar called on countries to "review" Israel ties and urged US pressure to rein in its ally.

The emir told the meeting that Israel's attack was an attempt to "thwart the negotiations" to end the Gaza war.