Blinken tells Netanyahu in Israel: US not going anywhere

US Secretary of State Antony Blinken on Thursday reassured Israeli Prime Minister Benyamin Netanyahu of Washington's support, during a trip to the Middle East that aims to prevent the conflict with Palestinian Hamas militants from spreading.

Blinken has embarked on a multi-country Middle East tour as Israel unleashes the most powerful bombing campaign in the 75-year history of its conflict with the Palestinians, vowing to annihilate Hamas - which rules the Gaza Strip - in retribution for the militants' weekend attacks.

Washington's top diplomat will also try to help secure the release of hostages kidnapped by Hamas, some thought to be Americans, and advance talks with Israelis and Egyptians on providing a safe passage for Gaza civilians out of the enclave before a possible Israeli ground invasion.

Blinken's trip also aims to send a deterrence message to Iran, which backs Hamas, to not get involved in the conflict.

An hour after landing in Tel Aviv, Blinken shook hands with Netanyahu and told the prime minister: "We're here, we're not going anywhere," footage from Netanyahu's office showed.

After Israel, Blinken will head to Jordan to meet with King Abdullah and Palestinian Authority President Mahmoud Abbas. He is likely to continue onto other Arab countries, US officials say, without specifying which.

Read More: Iran's Khamenei says Tehran was not behind Hamas attack on Israel

Israel has vowed retribution for the deadliest attack on Jewish civilians since the Holocaust, when hundreds of Hamas gunmen poured across the barrier fence and rampaged through Israeli towns on Saturday.

Israel said on Thursday there would be no humanitarian break to its siege of the Gaza Strip until all hostages taken by Hamas were freed.

Read More: Israel forms emergency government against Hamas as deaths and damage in Gaza mount

A senior State Department official, speaking to reporters on the condition of anonymity, said Washington was working to advance talks on providing a safe passage to civilians, including Americans in Gaza.

"There's a community of something in the order of 500 to 600 Palestinian Americans, more or less, resident in Gaza. Some of them want to leave...and we are working to organize safe passage," the official said.

Making sure the conflict does not expand has also been a top priority for Washington and Blinken has been speaking with regional allies, which speak to Iran and Iran-backed groups, to ask them to advise Tehran to keep out.

"We're very intent on demonstrating ... that we're committed to keeping other parties out of this conflict," the official said.

Speaking to Jewish community leaders in Washington on Wednesday, U.S. President Joe Biden said the deployment of US warships and aircraft closer to Israel should be seen as a signal to Iran, which has denounced US interference in the region.

"We made it clear to the Iranians: Be careful," Biden said.