Barack Obama has said Israel has “no greater friend” than the US, as he makes his first visit to the country as president.
Arriving in Tel Aviv, Mr Obama told PM Benjamin Netanyahu the US was proud to be Israel’s “strongest ally”, and that “peace must come to the Holy Land”.
On Thursday, Mr Obama will travel to the West Bank city of Ramallah to meet Palestinian President Mahmoud Abbas.
Peace talks, Syria and Iran’s nuclear plans are expected to dominate talks.
But US officials have tried to lower expectations of any significant headway on restarting the Israeli-Palestinians peace process.
Correspondents say Israelis are more preoccupied with instability in the wider Middle East region than with breathing new life into the peace process, which broke down in 2010 amid a dispute over continued Israeli settlement construction.
Settlement supporters are a big force in Israel’s new coalition government.
‘Eternal alliance’
Mr Obama was welcomed at Ben Gurion airport by Mr Netanyahu and Israeli President Shimon Peres.
He was introduced to Israeli ministers and leaders of religious communities and later shown a missile battery that forms part of Israel’s Iron Dome defence system against rocket attacks.
“Even as we are clear eyed about the difficulties, we will never lose sight of the vision of an Israel at peace with its neighbours,” he said in brief comments.
He added: “The United States stands with Israel because it is in our fundamental security interests to stand with Israel. Our alliance is eternal. It is forever.”
Mr Netanyahu thanked Mr Obama for “unequivocally affirming Israel’s sovereign right to defend itself by itself against any threat”.
Mr Obama later visited Mr Peres at his official residence.
In a joint news conference, the Israeli president said the two nations were united by a common vision – to confront dangers and bring peace.
He said he trusted the US in its policy of preventing Iran from developing nuclear weapons.
Mr Obama said he had reassured Mr Peres “that in this work Israel will have no greater friend than US”.
Mr Obama then went on to talks with Mr Netanyahu. On Thursday, he will travel to the West Bank to meet Palestinian President Mahmoud Abbas.
At home, Mr Obama has been criticised for not having visited Israel in his first term as president, with some saying it shows he is not close enough to the country.
The state of the economy and social issues dominated Israel’s last election, and the president has said he is not going to the region bearing any grand peace plan.
But with warnings that time is running out for a two-state solution to the Israeli-Palestinian conflict, some still think he will try to lay the ground for some greater effort to restart talks, BBC North America editor Mark Mardell reports from Jerusalem.
The president’s relationship with Mr Netanyahu has been notoriously frosty and one recent opinion poll suggested a mere 10% of the Israeli public had a favourable opinion of the US president.
‘Slap in the face’
The main event of this trip is a speech to Israeli university students on Thursday. The president’s main task is to build bridges and improve his image, which could give him more leverage over the new Israeli government, our correspondent adds.
Thousands of Israeli and Palestinian security officers have been assembled in Jerusalem and the Palestinians’ de facto capital in the West Bank city of Ramallah, ahead of his trip.
Both Israeli and Palestinian groups have staged protests in the run-up to Mr Obama’s visit.
In the West Bank city of Hebron, protesters wearing masks of Mr Obama and civil rights leader Martin Luther King called for an end to “apartheid”.
There were clashes between the pro-Palestinian protesters and some of the settlers living in the divided city, and a number of Palestinians were arrested.
In Gaza City, protesters burned US flags outside UN offices, the Associated Press reports.
One protester said the visit would “only bring us shame and add more humiliation on to us”, Reuters reports.
Hamas spokesman Sami Abu Zuhri said the visit was “ominous” and unwelcome, and that its consequences would be negative.
“It gives legitimacy to the occupation and confirms the political support of the United States [to Israel],” AP quoted him as saying.
Meanwhile, Israelis have been staging protests in Jerusalem demanding Mr Obama free Jonathan Pollard, imprisoned in the US in 1987 for spying for Israel.