US President Donald Trump on Tuesday defied the wishes of world powers when he announced that Washington would pull out of the historic nuclear accord and impose new sanctions on Tehran.

Calling Trump's decision "wrong", Erdogan and Putin pointed out that the nuclear accord "was a diplomatic success which actually should be protected" during a telephone conversation on Thursday evening, the Turkish source said.

The Kremlin said in a statement that the two strongmen "emphasised that the safeguarding of the JCPOA (the formal abbreviation for the accord) is very important for international and regional security as well as the nuclear non-proliferation regime".

The two leaders "confirmed their determination" to continue to cooperate to this end with the other signatory countries of the agreement, the Kremlin added.

After long negotiations, Iran agreed in July 2015 to freeze its nuclear programme in return for the lifting of punishing international sanctions.

The deal had been negotiated between Iran and the five permanent members of the UN Security Council -- Britain, China, France, Russia and the United States -- plus Germany.

Erdogan also congratulated Putin on the start of his fourth term as president after the Russian leader was sworn in on Monday.

Ankara has been working closely with Moscow and Tehran over the past year on the Syrian peace process despite being on opposing sides of the conflict and having a sometimes troubled relationship with Iran.

According to Russian newspaper Kommersant, in the final year of Putin's third term as president, he spoke to Erdogan 20 times, double that of other world leaders.

Relations between Turkey and the US are strained over multiple issues including Washington's support for Syrian Kurdish militia which Turkey views as terrorists and the continued imprisonment of an American pastor in Turkey.

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