The Republican presidential hopeful accused his Democratic rival of putting "daylight between the US and Israel" during a heated exchange in Tuesday night's debate.

Mitt Romney said there were questions over his opponent's "whole policy" in the Middle East, citing the situations in Syria and Egypt and the recent fatal attack on the US envoy in Libya.

"We have Iran four years closer to a nuclear bomb," said Mr Romney. "The president's policies throughout the Middle East began with an apology tour and pursue a strategy of leading from behind, and this strategy is unravel l ing before our very eyes."

The debate, held at a university on Long island, was the second of three official ones being held in the run-up to November's election. In the first, President Obama was widely deemed to have been the weaker of the two, but Tuesday night's debate proved to be a more balanced and emotional contest.

President Obama did not refer directly to Israel in his response, but challenged Mr Romney for suggesting that he had not offered a strong response to the killing of the ambassador and three other Americans last month. " The suggestion that anybody in my team… would play politics or mislead when we've lost four of our own, is offensive. That's not what we do."

The president of the National Jewish Democratic Council, David Harris, said after the debate: "Governor Romney has tried time and time again to mischaracterise President Obama's relationship with Israel, ignoring that the relationship between these two countries is stronger than ever.

"He showed that he stands with the Jewish community on a wide range of issues from keeping America safe and fighting for economic justice to protecting a woman's right to choose."

One of Mr Romney's most important backers, the Jewish casino magnate Sheldon Adelson, has rep o rtedly given another financial boost to a rabbi running for Congress.

Mr Adelson had already donated $500,000 to a super political action committee backing Rabbi Shmuley Boteach's campaign to become a congressman in New Jersey. This week, it is understood that he matched that amount with a second donation to the campaign coffers of the former chaplain of Oxford University.