Iran is prepared to take a "stronger step" in reducing its commitments under the 2015 nuclear deal with world powers if European countries don't take action to save the pact, its foreign ministry's spokesman said on Monday.

Iran has said it will breach the deal's limits on its nuclear activities one by one, ratcheting up pressure on the countries who still hope to save it.

Tehran has threatened to take further steps by Sept. 6, such as enriching to 20% or restarting mothballed centrifuges, machines that enrich uranium.

"Iran is prepared for reducing its commitments if the European parties do not show enough determination... The third step has been designed and will be stronger than the first and second steps to create balance between Iran's rights and commitments to the JCPOA," state news agency IRNA quoted spokesman Abbas Mousavi as saying.

Iranian Deputy Foreign Minister for Political Affairs Abbas Araghchi is heading to Paris to hold talks with French officials about the deal.

Also, Iran's government spokesman said on Monday that Iran and France's views on the deal have moved closer, mainly after phone calls between President Hassan Rouhani and his French counterpart Emmanuel Macron.