Following recent comments by Russian Foreign Minister Sergey Lavrov and a meeting between Lavrov and his Iranian counterpart, Mohammad Javad Zarif, signs are emerging that Russia and the United States could be headed for a collision over Moscow’s economic relationship with Iran in the post-nuclear agreement era.

Lavrov was characteristically optimistic about Russia’s relations with Iran following his Aug. 17 meeting with Zarif in Moscow, citing “positive momentum” and announcing a planned meeting of the Permanent Russian-Iranian Commission for Trade and Economic Cooperation, probably in October. In welcoming Zarif in front of reporters prior to their discussions, he had been even more upbeat, referring to an “opportunity to take Russian-Iranian relations to a new level.”

Two days later in Sevastopol, Lavrov was forceful in asserting Moscow’s commitment to its ties with Tehran and Russia’s rejection of unilateral US sanctions, including the so-called secondary sanctions, those affecting firms outside the United States that deal with Iran.

Lavrov was in Sevastopol — at the southern end of the Russian-occupied Crimean Peninsula and the site of Russia’s principal naval base on the Black Sea — for a meeting of Russia’s Security Council, chaired by President Vladimir Putin. The decision to conduct the meeting in Crimea was clearly a symbolic one, relaying to Russians, Ukrainians, Americans and Europeans what Moscow thinks about Crimea’s status and Western pressure concerning it.