"I believe the only practical steps that need to be taken in order to resolve the situation... is to convince all remaining participants to fulfil their obligations," he said.

Lavrov said the 2015 deal had been "fragile" since US President Donald Trump announced Washington would pull out a year ago.

European signatories of the deal, known as the Joint Comprehensive Plan of Action (JCPOA), were trying to "divert attention" from their inability to implement points of the agreement, Lavrov said.

"We will call on them, as we have done before, to concentrate on implementing everything that is enshrined in the JCPOA and approved by the UN Security Council."

Zarif's Moscow visit came as Iran said it had stopped respecting limits on its nuclear activities agreed under the deal until other signatories find a way to bypass renewed US sanctions.

Washington reimposed sanctions after it quit the agreement one year ago, dealing a severe blow to the Iranian economy.