Israeli Prime Minister Benjamin Netanyahu says he will give international sanctions against Iran a chance to work, and is not planning an attack on its nuclear facilities in the coming “days or weeks.”

Speaking to Israeli television on Thursday, Mr. Netanyahu said he prefers a peaceful solution of the dispute with Iran, but insisted that his country will not allow Iran to obtain a nuclear weapon.

Mr. Netanyahu has just returned from talks in Washington, where he said Israel could not afford to wait much longer for diplomacy and sanctions to deter Iran's nuclear program.

The Israeli leader has acknowledged what he calls “fundamental differences” between the U.S. and Israeli approach to Iran. He says Israel feels the Iranian nuclear threat more acutely than does Washington.

“The American timetable in regards to preventing Iran becoming nuclear is not the same as the Israeli timetable. The Israeli timetable is of course under a different schedule. I would be happy if the international effort succeeded, if Iran voluntarily decided to disarm its nuclear plan.”

President Barack Obama has urged Mr. Netanyahu to give diplomacy and sanctions more time, but also has reiterated the U.S. position that all options are on the table to stop Iran from obtaining a nuclear weapon.

U.S. Senator John McCain told Alhurra TV on Thursday that sanctions are failing.

“The sanctions that have been imposed on Iran, in the view of every expert, have not changed their course toward obtaining nuclear weapons.”

McCain was Mr. Obama's Republican Party opponent in the 2008 presidential election. He said he agrees with the assessments of senior U.S. military officials who see the potential fall of the government of President Bashar al-Assad in neighboring Syria as the biggest blow to Tehran in 25 years.

Meanwhile, a group of six world powers on Thursday called on Iran to keep its promise to allow International Atomic Energy Agency inspectors access to a military site amid reports Tehran may be cleaning it of evidence related to nuclear arms experiments.

The statement by the five permanent members of the U.N. Security Council – the United States, China, Russia, France and Britain – plus Germany urged Iran to allow inspectors prompt access to the Parchin military base.

Some Western diplomats believe Iran might be delaying the inspectors' trip to the base in order to remove evidence of experiments on nuclear-related high explosive trigger tests, citing recent satellite pictures showing apparent changes to its structure.

Iran's IAEA ambassador, Ali Asghar Soltanieh, told reporters the suspicions aired about Parchin were “childish” and “ridiculous.” He did not elaborate.

Iran denies allegations it is attempting to develop atomic weapons and says its nuclear activities are purely for power generation and medical research purposes.