Russia has said that the use of Iranian air base to bomb Islamic State (Isis) militants and other jihadist groups by it did not violate a UN Security Council (UNSC) resolution which prohibits supply of war planes to Tehran.

Russian Foreign Minister, Sergei Lavrov on Wednesday (17 August) told Russia's state news agency TASS that "No supplying, selling or transferring of warplanes to Iran has occurred."

Lavrov's response comes after US State Department spokesperson Mark Toner, on Tuesday said that Russia could be violating UN security resolution 2231, which was passed as a part of the Iran nuclear deal in July 2015.

Toner said, "As I understand it, it's not just supplying the Iranians certain weapons or certain offensive weaponry. It's more complex than that. Our lawyers are looking at it. We haven't made an assessment." He added that Russia's decision was "unfortunate but not surprising or unexpected" Toner stated that the US was still considering a deal with Russia to fight IS (Daesh) in Syria but "we have certain issues that we want resolved" before entering into any such deal.

According to the resolution, Iran will under no circumstances ever seek or develop or acquire any nuclear weapons. It also prevents any supply, sale or transfer of combat planes to Iran unless approved by the UNSC in advance.

Meanwhile, Russia's defence ministry on Wednesday said that its war planes took off from an Iranian air base and conducted air strikes against IS (Daesh) in Syria's Deir al-Zour province, on day two of the bombing campaign. The first wave of air strikes took place on Tuesday.

The raids struck two major Isis command centres and training camps "eliminating more than 150 militants" Russian state news agency TASS said.