An Israeli attack on Iran would delay but probably not stop its nuclear programme, the most senior US military officer claimed on Thursday. General Martin Dempsey reinforced Washington's opposition to unilateral Israeli military action as he made clear that US military chiefs were equally wary of getting ensnared in Syria.

In common with Nato's supreme commander, US admiral James Stavridis, who writes in today's London-based Guardian, Dempsey put a brave face on the situation in Afghanistan. The chairman of the joint chiefs of staff was speaking in London, where he attended the opening ceremony of the Paralympic Games as head of the US delegation.

Distancing himself from any Israeli plan to bomb Iran, Dempsey said such an attack would “clearly delay but probably not destroy Iran's nuclear programme”.

He added: “I don't want to be complicit if they (Israel) choose to do it.”

Dempsey said he did not know Iran's nuclear intentions, as intelligence did not reveal intentions. What was clear, he said, was that the “international coalition” applying pressure on Iran “could be undone if (Iran) was attacked prematurely”. Sanctions against Iran were having an effect, and they should be given a reasonable opportunity to succeed.

The US, like the UK, was supplying “non-lethal” aid to Syrian rebels. What he described as “any broader activities inside Syria” would have to be discussed and conducted within the Nato framework, Dempsey said.

In Afghanistan, the Taliban were using young men in “green on blue” attacks — attacks by Afghans in army uniform — as part of a new asymmetric weapon, as improvised explosive devices had been in the past, Dempsey suggested.

A rapid expansion of Afghan security forces from 200,000 to more than 300,000 in two years had “exposed vulnerabilities in vetting practices”, he said.

Stavridis writes in the Guardian that “substantial progress” has been made in Afghanistan in three areas. Firstly, Afghanistan is no longer a safe haven for terrorists. Secondly, national forces have improved over the past 18 months, “to the point where they are making significant gains in the fight against the Taliban”. Thirdly, the international community has made specific pledges on long-term partnerships with Afghanistan.

Stavridis said Afghan society was changing for the better every day, but “I have no doubt that there will still be difficult days ahead.”

By arrangement with the Guardian