The US should not become embroiled in an Israeli military strike on Iran that would not only fail to destroy Iran’s nuclear program, but could also undo international diplomatic pressure on Tehran, the Chairman of the Joint Chiefs of Staff General Martin Dempsey said Thursday in London.

Such an attack by Israel would “clearly delay but probably not destroy Iran’s nuclear program,” Dempsey said, adding: ”I don’t want to be complicit if they [Israel] choose to do it.”

The US’s top general – the Guardian reported – said that he could not presume to know Iran’s ultimate intentions in pursuing a nuclear program, as intelligence was inconclusive on that score. It was clear, however, he maintained, that mounting pressure from the American-led “international coalition… could be undone if [Iran] was attacked prematurely.”

Last week, Dempsey said that Israel and the US did not see eye to eye on the Iranian nuclear threat, admitting that Washington and Jerusalem were on “different clocks” regarding Tehran’s nuclear ambitions.

He noted, however, that he understood Israel’s urgency in calling for action against Iran’s nuclear program.

“They are living with an existential concern that we are not living with,” he said.

Dempsey added that he and Israeli Defense Forces Chief of General Staff Lt.-Gen. Benny Gantz spoke on a bi-weekly basis to coordinate intelligence, despite gaps in understanding how close Iran was to a breakout nuclear capability.

“We compare intelligence, we discuss regional implications. And we’ve admitted to each other that our clocks are turning at different rates,” he said.

Thursday’s comments from Dempsey, who was in London for the Paralympic Games, come amid mounting chatter over a possible Israeli strike on Iran’s nuclear program. The US has been working to keep Israel from launching a unilateral strike, maintaining that sanctions should be given more time to work.

Last week, the former American ambassador to Israel, Martin Indyk, termed Israel’s talk of attacking Iran “a classic case of crying wolf.”

Joshua Davidovich contributed to this report.