Mitt Romney has angered Palestinians with his hint that he will recognise Jerusalem as Israel's capital should he win November's presidential election.
The Republican hopeful, who visited Israel after a less-than-successful stop in Britain, said he believed the city was the Jewish state's capital. He also suggested that he would move the US embassy in Israel from Tel Aviv to Jerusalem if he was elected; something Israeli advocates have been campaigning for for years.
He told CNN while in Jerusalem: "My understanding is the policy of our nation has been a desire to move our embassy ultimately to the capital. I would only want to do so and to select the timing in accordance with the government of Israel."
The chief Palestinian negotiator Saeb Erekat labelled the former Massachusetts governor's remarks "absolutely unacceptable".
"Such statements and policy will push the region toward extremists," he said.
But he expressed doubt that Mr Romney would enact such a change if he defeated Barack Obama. "At the end of the day, the US has embassies in 57 Arab and Muslim countries," he said. "I don't think they will sacrifice everything for such statements."
Earlier, Israeli Prime Minister Benjamin Netanyahu welcomed Mr Romney – with whom he worked in the 1970s - to Israel. "In this great convulsion, there is one stable, democratic ally of the United States here in the Middle East, and that's Israel," he said. "Strengthening the relationship between America and Israel is in the interest of peace, in the interest of both our countries, and I believe that your visit is an expression of that desire on both of our peoples."
Mr Romney, who was joined by the casino magnate and Republican donor Sheldon Adelson during his stay, will now visit Poland on the final stop of his international tour, before heading back to the US for the Republican Party convention.