Russian Deputy Foreign Minister Sergei Ryabkov warned on Wednesday that direct US military assistance to Israel could radically destabilise the situation in the Middle East, where an air war between Iran and Israel has raged for six days.

In separate comments, the head of Russia’s SVR foreign intelligence service, Sergei Naryshkin, was quoted as saying that the situation between Iran and Israel was now critical.

Ryabkov warned the US against direct military assistance to Israel or even considering such “speculative options,” according to Russia’s Interfax news agency.

“This would be a step that would radically destabilise the entire situation,” it cited him as saying.

Earlier, a source familiar with US internal discussions said President Donald Trump and his team were considering a number of options, including joining Israel in strikes against Iranian nuclear sites.

On Tuesday, Trump openly mused on social media about killing Iran’s Supreme Leader Ayatollah Ali Khamenei, but said “We are not going to take him out (kill!), at least not for now.”

Israel launched air strikes last Friday against Iran’s nuclear sites, scientists and top military leaders in a surprise attack that Russia condemned as unprovoked and illegal. Iran has responded with missile and drone attacks on Israeli cities.

Russian President Vladimir Putin, who in January signed a strategic partnership treaty with Iran, has called for a cessation of hostilities between the two sides.