Russia's President, Vladimir Putin, is due in Tehran tomorrow for a high profile visit, despite rumours of an assassination attempt.
He is to attend a summit of Caspian Sea heads of state and then hold talks with Iranian leaders.
Russia's Interfax news agency, citing a source in the Russian special services, had reported that a group of suicide bombers would try to kill Mr Putin while he was in Tehran.
Iran's foreign ministry reacted furiously to the reports, describing them as completely without foundation.
It said they were part of a psychological war waged by enemies to disrupt relations between Iran and Russia.
Foreign ministry spokesman Mohammad Ali Hosseini today insisted the visit was still going ahead and even gave a full itinerary for the presidential visit.
And Mr Putin's spokesman, Dmitry Peskov, told reporters in the Iranian capital he had no information of a change of plan.
The planned visit comes at a time of mounting international frustration with Iran for its alleged support for Shia militants in Iraq and as well as its defiant refusal to suspend sensitive activities in its nuclear programme.
Iran has regularly hosted allies who share its antipathy towards the US, like Belarus President Aleksander Lukashenko, Syrian President Bashar al-Assad, or Venezuela's Hugo Chavez.
But a visit by a statesman of Mr Putin's stature - whose country has veto powers as a permanent member of the UN Security Council - is a major event.
The last Kremlin chief to visit Iran was Joseph Stalin, who attended the famous conference of the World War II 'Big Three' Allied powers in Tehran in 1943 alongside Winston Churchill and Franklin D Roosevelt.
