White House hopeful Barack Obama stepped into the maelstrom of the Middle East, stating ahead of talks with Israeli leaders he would strengthen US bonds with Israel if elected president.

The Democratic senator, on a high-risk tour to prove his diplomatic and commander-in-chief credentials, arrived in Jerusalem late on Tuesday for a packed presidential-style schedule after visiting Iraq and Jordan.

But regional tensions immediately intruded, as a Palestinian man was shot dead after launching a bulldozer rampage which wounded at least 16 people near Jerusalem's King David Hotel where Obama was to stay.

Obama condemned the attack, saying it was "a reminder of what Israelis have had to courageously live with on a daily basis for far too long," and promised to vigorously join the search for Middle East peace if he is elected in November.

The Illinois Senator, who is being advised by ex-president Bill Clinton's former Middle East envoy Dennis Ross, backed the two state solution to the Israeli-Palestinian conflict.

Special relationship

After touching down at Tel Aviv airport after a short flight from Jordan, Obama made a brief statement, saying it was "wonderful to be back in Israel."

"I want input and insight from Israeli leaders about how they see the current situation, I will share some of my ideas," Obama said.

"The most important thing for me to share is the historic and special relationship between the United States and Israel, one that cannot be broken."

"One that I have affirmed throughout my career and one that I will intend to not only continue but strengthen in an Obama administration."

Obama's audience for this visit is not just in the Middle East, but back at home where he has struggled to win the overwhelming support among American Jewish voters enjoyed by some previous Democratic candidates.

Earlier, a day before meeting Israeli and Palestinian leaders, he warned that entrenched positions, divisions among Palestinians and turbulent Israeli politics meant progress could be slow.

"It is a very difficult process. There is a lot of history that exists between those two people. That history is not going to vanish overnight.

"So I think it's unrealistic to expect that a US president alone can suddenly snap his fingers and bring about peace in this region."

While Obama is likely to be greeted as a hero in Europe, there remain questions in the Middle East about his potential policies.

His view that Jerusalem must remain the undivided capital of Israel sparked fury among Palestinians, who saw it as pre-judging final status talks, while his offer to talk to Iran is likely to face scrutiny in Israel.

Israel tightened security

Israeli police said they had tightened security immediately after the bulldozer attack — the second such incident in three weeks — and that the state of alert would remain until after Obama's visit.

The White House urged "all parties" in the Middle East to condemn the attack if Israel determines it was an act of terrorism.

"Terrorist attacks do nothing to further the goals of Israel and Palestine living side by side in peace, a goal the president has been advocating for, and that both of those countries' leaders have been working toward," said spokesperson Dana Perino.

Obama condemned the attack, telling reporters in Jordan where he held talks with King Abdullah II that he would support Israel "in confronting terrorism and pursuing lasting peace and security."

A Jordanian palace statement said that in his talks with Obama, King Abdullah had stressed that ending the Israeli occupation of Palestinian land and achieving a just settlement to the Arab-Israeli conflict "tops the priorities of the people of the Middle East."

"The king told Obama that continued American support for a Middle East peace process that leads to a just and comprehensive peace would help foster Arab-US relations and bolster US credibility in the region," the statement added.

Obama will on Wednesday meet Prime Minister Ehud Olmert, President Shimon Peres, Foreign Minister Tzipi Livni, opposition Likud party chief Benjamin Netanyahu and Defence Minister Ehud Barak, and then hold talks with Palestinian President Mahmud Abbas in Ramallah.

From Israel, Obama will head to Germany for the symbolic centrepiece of his campaign swing, a major open-air speech in Berlin on US transatlantic relations.