Iran says Russia will no longer use the Hamedan air base to launch air strikes in Syria but parties could reach another agreement in future depending on the situation in the region.
The Iranian foreign ministry said on Monday that Iran's agreement with Russia to allow the use of the Hamedan air base for launching air strikes in Syria is over for the time being.
Bahram Ghasemi, the spokesman for Iran's foreign ministry, told reporters in Tehran that Russia's "mission was a specific, authorised mission and it's over for now."
But Ghasemi pointed at a possibility of reaching another agreement with Russia in the future if circumstances warrented.
A Russian Defence Ministry spokesman Major General Igor Konashenkov also said in a statment that Russian military aircraft that took part in the operation from Hamedan have successfully completed all tasks.
"Further use of the Hamadan air base in the Islamic Republic of Iran by the Russian Aerospace Forces will be carried out on the basis of mutual agreements to fight terrorism and depending on the prevailing circumstances in Syria," Konashenkov said.
The Russian aircraft's presence in Hamedan was the first time since World War Two that a foreign power used an Iranian base for operations. Russia and Iran are providing crucial military support to Syrian regime leader Bashar al Assad against opposition groups in Syria's five-year-old conflict.
Russian MoD released footage of Su-34s flying from Hamedan (Iran) releasing maximum combat load over Syria pic.twitter.com/9ymDByAapH— BM-21 GRAD (@bm21_grad) August 17, 2016
The activists in Syria accuse both countries of targeting civilians in opposition-held neigbouroods instead of the DAESH terrorist organisation.
According to some Iranian lawmakers, the move was a breach of the Iranian constitution which forbids "the establishment of any kind of foreign military base in Iran, even for peaceful purposes".
Iranian Defence Minister Hossein Dehghan denied that Tehran provided a "written permission" to Russia and criticised Moscow for publicising the move, describing it as showing off and a "betrayal of trust".
"We have not given any military base to the Russians and they are not here to stay," Dehghan was quoted as saying by the Fars news agency late on Sunday.
But the US State Department said it was "unclear" whether Russia's use of the base had "definitely stopped" after calling the move "unfortunate but not suprising". The State Departmnet also stated that it was studying if it violated a UN Security Council resolution that bars the supply, sale and transfer of combat aircraft to Iran.
While noting that Iran has long supported Assad, a US official said Tehran may not have wanted its involvement to be so public ahead of the 2017 Iranian presidential election.
"The Iranians don't mind helping out quietly. They just don't want the world to know that they are contributing to the deaths of thousands of Syrian civilians," said the US official, who spoke on the condition of anonymity.
The statements came one day after a military souce told the Russian news agency Interfax that the Russian Defence Ministry sent a request to Iraq and Iran for the use of their air space for the flight of ballistic missiles from the Caspian Sea.