Russian Foreign Minister Sergei Lavrov has warned that Iran's nuclear deal with world powers will collapse if the US withdraws from the agreement.

"It cannot keep alive in a re-negotiated form, especially regarding the demands by the United States. It would not be acceptable for Iran and it is clear now, I believe, that the Europeans do understand this danger right now," Lavrov told reporters at the UN on Friday..

"This agreement cannot be implemented if one of the participants unilaterally steps out of it. It will fall apart, there will be no deal then," he noted

The Russian foreign minister said he believed Washington was "going to try to convince the European states to take the same position that Washington has taken."

Lavrov said on Monday that Moscow will not back US attempts to change the 2015 nuclear deal, known as the Joint Comprehensive Plan of Action (JCPOA).

Read more:

Last week, US President Donald Trump extended waivers of economic sanctions on Iran for another 120 days but said he was doing so “for the last time.”

US President Donald Trump addresses the National Assembly in Seoul on November 8, 2017. (AFP photo)

Although the US president declined to withdraw from the Iran deal — which he has long railed against and formerly promised to “rip up” — he gave a four-month deadline to the US Congress and America’s main European allies to address what he called the “disastrous flaws” of the deal.

The agreement, reached between Iran and the P5+1 countries -- the US, the UK, France, China, Russia and Germany -- puts limitations on parts of Iran’s nuclear program in exchange for removing all nuclear-related sanctions.

A decision to reimpose sanctions would have effectively ended the Iran nuclear agreement.

The European parties to the deal, China and Russia have made it clear that they will not reopen negotiations on the deal, which they say is working as it is; and Trump’s demands could thus only be addressed by domestic US law, with no jurisdiction over Iran or the International Atomic Energy Agency, and with no direct effect on the JCPOA.

Iran’s says the country would commit to no obligation beyond those it has already agreed to under the JCPOA and that it would not renegotiate the deal.