An Israeli airstrike on Iranian nuclear sites would be a "huge and highly complex" undertaking, U.S. media reported Monday, citing defense officials and military analysts close to the Pentagon.

The New York Times reported that to launch a strike against Iran, Israeli pilots would have to "fly more than 1,000 miles (more than 1,600 kilometers) across unfriendly airspace, refuel in the air en route, fight off Iran's air defenses, attack multiple underground sites simultaneously - and use at least 100 planes."

The newspaper quoted experts including David Deptula, who retired last year as the Air Force's top intelligence official, and Andrew Hoehn, director of the Rand Corp.'s Project Air Force, as saying the mission would be extremely difficult.

The experts' opinions echoed those of former CIA director Michael Hayden, who said last month that airstrikes capable of seriously damaging Iran's nuclear program were "beyond the capacity" of Israel.

An air raid on Iranian nuclear sites by Israel has become a hot topic in Washington, with pundits weighing in on how Israel could pull it off.

In a Sunday interview with the CNN, Martin Dempsey, chairman of the U.S. Joint Chiefs of Staff, said American officials have tried to persuade Israel from launching an attack on Iran.

"That's been our counsel to our allies, the Israelis," Dempsey said. "We also know, or believe we know, that the Iranian regime has not decided that they will embark on the efforts to weaponize their nuclear capability."

U.S. officials believe Iran is "a rational actor" and "the current path that we're on is the most prudent at this point," Dempsey said, noting that the economic sanctions on Iran are "beginning to have an effect."