The U.S. has decided to scale back its military exercise with Israel, planned for mid-October, Time Magazine reported on Friday.

The report quoted both Israeli and American sources as saying that Washington had slashed "by more than two-thirds the number of American troops going to Israel and reducing both the number and potency of missile interception systems at the core of the joint exercise."

The exercise, Austere Challenge 12, will be the latest in a series of periodic joint maneuvers focusing mainly on missile defense. The exercise will combine simulated missile fire with training for the command posts.

The current round will feature various intercept systems - Iron Dome, Arrow II, Patriot and Aegis - along with the American X-Band radar that is permanently stationed in the Negev.

According to the report in Time, however, the crews operating the Patriot missiles will not arrive in Israel as planned, and instead of the two Aegis Ballistic Missile Defense warships scheduled to arrive, only one might possible be dispatched.

"Basically what the Americans are saying is, ‘We don’t trust you,’” a senior Israeli military official told the magazine.

On Thursday, the Guardian reported that U.S. General Martin Dempsey said that an Israeli attack on Iran would delay but not stop its nuclear program.

"I don't want to be complicit if they [Israel] choose to do it," Dempsey said.