Rubio scheduled a solidarity visit a week before a French-led summit at the United Nations to recognise a Palestinian state, a prospect fervently opposed by Netanyahu's right-wing government.

But talks will instead be more difficult as President Donald Trump's administration was caught off guard last week when Israel carried out an attack in Qatar against Hamas leaders who were meeting to discuss a new US ceasefire proposal for Gaza.

Trump, for years a fervent defender of Netanyahu, on Sunday again voiced support for Qatar, which is home to the largest US air base in the region and has assiduously courted the US president, including by gifting a luxury jet.

"Qatar has been a very great ally. Israel and everyone else, we have to be careful. When we attack people we have to be careful," Trump told reporters.

Rubio, who will later address the press with Netanyahu, said as he left Washington on Saturday that "obviously we're not happy" about the strike but added: "Now we need to move forward and figure out what comes next".

Rubio said he would speak to Netanyahu about Israeli military plans to seize Gaza City, the largest urban centre in the devastated territory, as well as the government's talk of annexing parts of the occupied West Bank in hopes of precluding a Palestinian state.

Rubio said Trump wants the Gaza war to be "finished with" -- which would mean the release of hostages and ensuring Hamas is "no longer a threat".

The war was sparked by Hamas's October 7, 2023 attack on Israel, which resulted in the deaths of 1,219 people, most of them civilians, according to an AFP tally of official figures.

Israel's retaliatory campaign in Gaza has killed at least 64,871 people, also mostly civilians, according to figures from the health ministry in Hamas-run Gaza that the United Nations considers reliable.

- 'Eternal capital' -

The United States has not joined European powers in pressing Israel to end the offensive, who fear it will aggravate the already severe humanitarian crisis in the Gaza Strip, where most of its 2.4 million people have been displaced at least once since the outbreak of the war.

Despite the objections over the Qatar strike, Rubio opened the visit on Sunday with another show of support as he joined Netanyahu at the Western Wall, the holiest site where Jews are allowed to pray.

With Rubio at his side, Netanyahu said the Israel-US alliance has "never been stronger" and is "as strong, as durable as the stones in the Western Wall that we just touched".

Rubio, a devout Catholic, later posted that his visit showed his belief that Jerusalem is the "eternal capital" of Israel.

Until Trump's first term, US leaders had shied away from such overt statements backing Israeli sovereignty over contested Jerusalem, which is also holy to Muslims and Christians.

Trump moved the US embassy to Jerusalem, in a sharp break with most of the world.

Hamas called Rubio's visit a "blatant assault on the sanctity" of the Al-Aqsa Mosque, the Muslim sacred site above, and a "flagrant violation of the historical and legal status quo in occupied Jerusalem".

- Controversial tunnel -

Rubio separately is expected Monday to attend the inauguration of a tunnel for religious tourists that goes underneath the Palestinian neighourhood of Silwan to the holy sites.

The project has stirred fears among Palestinian residents that it could further dilute their presence, allowing Israelis to bypass Palestinians and possibly putting at risk the physical foundations of their homes.

Fakhri Abu Diab, 63, a community spokesman in Silwan, said Rubio should instead come see homes, such as his own, that have been demolished by Israel in what Palestinians charge is a targeted campaign to erase them.

"Instead of siding with international law, the United States is going the way of extremists and the far right and ignoring our history," he said.

Rubio played down the political implications, calling it "one of the most important archaeological sites in the world".