The Australian - The Kremlin's spokesman says US Secretary of State Mike Pompeo didn't offer President Vladimir Putin any reassurances or ease Moscow's concerns over the ongoing crisis between the United States and Iran.

Pompeo met with Putin on Monday in Russia's resort of Sochi where he sought to alleviate some of the concerns about the spiralling tensions but made clear the US would respond to any attacks on American targets.

Putin's spokesman Dmitry Peskov told reporters on Wednesday that Moscow is concerned over mounting tensions and defended Iran's actions as a legitimate response to the US decision to withdraw from the 2015 nuclear deal.

Iran has given European countries a 60-day deadline to negotiate a new nuclear deal Tehran or it would start enriching uranium to higher levels than outlined in the current agreement.