While Russia has engaged in a stand-off with the USA over former’s invasion of Ukraine that should not stop the resumption invasion of Ukraine of the Joint Comprehensive Plan of Action (JCPOA) between the P5 countries and Iran, popularly known as the Iranian nuclear deal. Basically, the deal was for the P5 countries, especially the Santo remove sanctions from Iran, while Iran was supposed to stop is enrichment of uranium to weaponization levels. It was an illustration of the power of sanctions, for sanctions had apparently forced Iran to accept the restrictions on what it still insists is a peaceful Nuclear Programme.
That might be the reason why Russia has stipulated that sanctions imposed on it due to its invasion of Ukraine should not apply to activities with Iran. It probably has in mind extensive oil and gas contracts with Iranian companies. Those contracts have been held up because sanctions were re-imposed by the USA after the Obama Administration, which negotiated and signed the original deal, gave way to the Trump Administration, which withdrew from the JCPOA in May 2018. The withdrawal had been made on the pressure from Israel, which had a disproportionate influence in Washington during the Trump era, and because it was an achievement of President Obama, and thus irritated President Trump no end. With the election of Joe Biden, who had been Obama’s Vice-President and to that extent was invested in the JCPOA, the USA started negotiations in Vienna, for re-entry into the JCPOA, along with the other P5 counties and the EU. The agreement could have come unstuck on Russia’s holding out, unless it was assured that it would not have its Ukrainian sanctions extended to this.
The oil price rise because of the Ukraine war is expected to come down with Iran being allowed to sell its crude, something which it was not previously allowed to do. Apart from benefiting from this fall in international oil prices, Pakistan has a particular interest in the lifting of sanctions, as it paves the way for the completion of the gas line supposed to go to India, which had been stalled because of the sanctions. While the USA could have easily made Ukraine an excuse, by letting Russia come on board, it has benefited the world, but itself as well.