A gang of suicide bombers were plotting to assassinate President Putin during his historic visit to Iran, it was alleged last night.

The Kremlin confirmed that President Putin had been told of a conspiracy to kill him during his trip to Tehran for a summit of Caspian Sea nations tomorrow. The Interfax news agency reported that Russian special services had learnt that a team of suicide bombers and kidnappers had been training to kill or capture the Russian leader.

A Kremlin spokeswoman confirmed that the President had been informed of a plot but declined to comment further.

Iran dismissed the report last night, however, as “completely without foundation”. Muhammad Ali Hosseini, the Iranian foreign ministry spokesman, said that the alleged plot was “part of a psychological war waged by enemies to disrupt relations between Iran and Russia”.

Interfax reported that several teams of suicide bombers had been preparing to kill President Putin in Iran. It said that “a reliable source” in one of the Russian special services had received the information from foreign contacts.

The Russian President arrived in Germany yesterday evening for a meeting with Angela Merkel, the Chancellor, and is due to fly on to Tehran tonight. He is the first Kremlin leader to visit Iran since Joseph Stalin flew to a summit with Winston Churchill and Franklin D. Roosevelt, his wartime allies, in 1943.

He is to meet Mahmoud Ahmadinejad, his Iranian counterpart, and take part in the Caspian nations summit tomorrow with the leaders of Iran, Azerbaijan, Kazakhstan and Turkmenistan, where they will discuss dividing up the energy-rich sea.

It was unclear last night who the alleged plotters were and why Iran was chosen for any assassination attempt. Russia is opposed to demands from the United States and other Western nations for tougher United Nations sanctions against Tehran over its nuclear ambitions. It is one of the few countries that has maintained good relations with Tehran and is continuing to build a nuclear power plant at Bushehr for Iran. The US and European powers accuse Iran of secretly trying to develop nuclear weapons, although President Ahmadinejad insists that the programme is purely for civil energy purposes.

Under threat

— Security officials in Ukraine foiled an assassination attempt on President Putin in Yalta in 2000

— Azeri secret service uncovered a plot against him in Baku, the capital, in 2001

— The Kremlin linked both alleged attempts to Chechen terrorists. Mr Putin, as Prime Minister, sent troops into Chechnya in 1999 to crush separatists

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