Republican presidential candidate Mitt Romney wants to boost military help to Israel, his campaign said Sunday, a day after he seemed to back starting the ally's aid package at zero.

"Mitt Romney firmly believes that the United States must continue supporting Israel and increase military aid to our strongest friend and ally," spokeswoman Andrea Saul told AFP by email.

Texas Governor Rick Perry, one of Romney's rivals for the party's nomination to take on President Barack Obama next year, said at a foreign policy debate late Saturday that if elected would completely overhaul US overseas assistance.

"The foreign aid budget in my administration for every country is going to start at zero dollars," followed by a national debate on "whether or not a penny of our taxpayer dollars needs to go into those countries," said Perry.

Pressed on whether that would apply to Israel, Perry replied that it is a "special ally" that would ultimately get "some substantial level" of aid "but it makes sense for everyone to come in at zero and make your case."

In response to a question about Pakistan, Romney declared that "one of the things we have to do with our foreign aid commitments, the ongoing foreign aid commitments -- I agree with Governor Perry. You start everything at zero."

"Governor Romney was talking about Pakistan when he said the foreign aid each year should start at zero," Saul stressed.

Perry's campaign released a statement after the debate describing him as "a friend to Israel" who "understands the challenges faced by the country," which is "a unique and vital political and economic partner for the United States."

The issue of US backing for Israel is politically important ahead of the November 2012 elections: Republicans rely on conservative Christians who support that US ally and hope to dent Obama's support among Jewish voters by portraying him as an unsteady friend to Israel.