Russia on Tuesday vowed to stand by its ally Iran and resist attempts to promote an anti-Iranian agenda amid tensions over Tehran's nuclear programme.
Foreign Minister Sergei Lavrov made the comments during a visit to Moscow by his Iranian counterpart Javad Zarif, as Iran sought to fend off criticism over granting access to sites where past nuclear activity may have occurred.
The standoff comes as a landmark deal brokered in 2015 between Iran and world powers to limit Tehran's nuclear programme continues to unravel.
"We will be doing everything so that no one can destroy these agreements," Lavrov told reporters after talks with Zarif.
Lavrov accused the United States of trying to "manipulate" the United Nations Security Council in order to put pressure on Iran.
"Washington has no right to punish Iran" by leveraging the UN Security Council, Lavrov said, adding that US plans to extend an arms embargo on the Islamic republic "contravene international law."
Moscow's top diplomat said at the start of the talks that Russia would firmly oppose any attempts "to promote an anti-Iranian agenda".
Zarif described developments around the Iranian nuclear deal -- formally known as the Joint Comprehensive Plan of Action -- as "very dangerous".
Iran had committed to curb its nuclear activities for sanctions relief and other benefits.
But Tehran has slowly abandoned its commitments since US President Donald Trump's decision two years ago to renounce the deal and reimpose sanctions.
Iran's stockpile of enriched uranium is now almost eight times the limit fixed in the accord, according to an assessment by IAEA, the UN nuclear watchdog.
However, the level of enrichment is still far below that needed for a nuclear weapon.
The head of the IAEA on Monday called on Iran to allow prompt access to two sites where past nuclear activity may have occurred.
In Moscow, Zarif implied Washington was also using the International Atomic Energy Agency to further its own interests.
Iran "won't allow the IAEA to become an instrument of abuse" for countries that want to scrap the Iran deal and "destroy all international obligations," he said in translated remarks.
He added that Iran had fully cooperated with the IAEA.