Joe Biden has defended his imminent trip to Saudi Arabia, saying he will not avoid human rights issues on the final leg of his Middle East tour, despite refusing to commit to mentioning the murder of the dissident journalist Jamal Khashoggi when he meets the kingdom’s crown prince.

Speaking during a news conference with the interim Israeli prime minister, Yair Lapid, in Jerusalem on Thursday, the US leader said his stance on Khashoggi’s killing was “absolutely” clear.

US intelligence services concluded last year that Khashoggi’s 2018 killing at the Saudi consulate in Istanbul was approved by the powerful heir to the throne, Mohammed bin Salman. On the campaign trail, the president vowed to turn the conservative Gulf kingdom into a “pariah state”, but the turmoil in global oil markets unleashed by Russia’s invasion of Ukraine has forced a U-turn.

“I have never been quiet about talking about human rights,” the president said. “The reason I am going to Saudi Arabia though, is much broader, it’s to promote US interests.

“And so there are so many issues at stake, I want to make clear that we can continue to lead in the region and not create a vacuum; a vacuum that is filled by China and/or Russia.”

Biden embarked on his first visit to the region as president with engagements in Israel on Wednesday, a trip dominated by the threat posed to the region by the growing military capabilities of Iran and its proxies around the Middle East.

The Biden administration hopes that Israel’s new relationships with several Arab states – including a gradual warming of ties with Saudi Arabia, which vies with Tehran for regional hegemony – will strengthen a fledgling regional alliance against Iran.

After a cursory meeting with Palestinian leaders in Bethlehem on Friday, the president will fly to the Saudi city of Jeddah with the aim of convincing Gulf oil producers to increase supply, as well as lobbying for fully integrating Israel into the emerging regional defence architecture.

Iran was top of the agenda for Israeli officials on the second day of Biden’s visit, during which the president pledged that the US was prepared to use “all elements of its national power” to deny Iran nuclear weapons.

The “Jerusalem declaration”, a joint communique issued by Biden and Lapid after their meeting, reaffirmed an “ironclad” US commitment to Israel’s security, as well as Israel’s right to defend itself.

The two countries, however, continue to disagree on the utility of rescuing the landmark nuclear deal with Iran, abandoned by Donald Trump in 2018. Talks to revive the accord began in April 2021, but have made little progress.

The Islamic Republic could still be prevented from enriching uranium to the level needed to manufacture a nuclear bomb, Biden said, and “Diplomacy is the best way to achieve this outcome”, although the US is “not going to wait forever”.

Lapid, on the other hand, said: “The only thing that will stop Iran is knowing that if they continue to develop their nuclear programme, the free world will use force.”

The Jerusalem declaration offered little to the Palestinians other than a brief reaffirmation of Biden’s commitment to a two-state solution to the conflict. Israel made no mention of the peace process, instead promising to improve the economy and quality of life for the 5 million people living in the occupied Palestinian territories.

Biden has declined a request for an audience from the family of the Palestinian-American journalist Shireen Abu Aqleh, who the US state department concluded was accidentally killed by the Israeli army in May.

The family, who accused Biden’s administration of siding with Israel by not calling for a criminal investigation, have instead been invited for talks in Washington. Protests demanding justice for Abu Aqleh are planned for Friday morning outside a US-funded hospital in East Jerusalem which Biden is scheduled to visit.

Palestinian expectations for Biden’s trip to Bethlehem are low; Washington has not pressured Israel to return to the peace process, nor moved to curb Israeli settlement building in the occupied West Bank.

The administration has also not fulfilled a promise to reopen a US mission to the Palestinians in Jerusalem, which was closed by Trump after he recognised the divided city as Israel’s capital in 2017.