Anyone who thinks that Russia will "abandon" Iran, they should study Russia more.
Russia is ready to broker talks between the US and Iran, including on Tehran’s nuclear program and its regional proxy network, Kremlin spokesman Dmitry Peskov told Bloomberg on Tuesday. Trump expressed interest in talking to Iran about those issues, both in his phone call to Putin in February and via representatives at the high-level US-Russian meeting in Riyadh just days later, the news agency wrote, citing anonymous officials. “Russia believes that the United States and Iran should resolve all problems through negotiations,” Peskov told Bloomberg when asked about such contact. Moscow “is ready to do everything in its power to achieve this,” he added.
Exactly! Russia views Caspian region as an enormously important realm both in terms of trade between Iran and Russia and as a critical link in North-South Corridor. And then, there are simply neighborly and humanitarian considerations--Russia doesn't like her friendly neighbors to be assaulted, simple as that. Russians love peace and calm. Now, with the dynamics in Washington and elsewhere (such as reportedly halting military aid to 404 by the US), this kind of brokerage can help immensely.