"Medvedev noted with satisfaction the Iranian president's positive assessment of the Russian initiative, a plan of gradual restoration of trust to the Iranian nuclear program,” the Kremlin said, adding that both leaders had agreed to continue talks on this issue.

The two presidents spoke the next day after the EU officials reached a preliminary agreement, backed by the United States, to impose an embargo on the Iranian oil exports that make up 60 percent of the country’s revenues.

The oil embargo may leave Tehran without its second largest market since the EU states buy 450,000 barrels of Iranian oil per day (bpd). China, the main customer of Iranian oil, has already cut its orders by more than half this month.

Tensions between Washington and Tehran aggravated in late December when the Iranian Navy, involved in the Velayat-90 military drills, discovered an American aircraft carrier nearby.

The situation around the maneuvers escalated when Iranian authorities said they might close the Strait of Hormuz which accounts for one-third of the world's tanker-borne oil and 17 percent of all oil traded worldwide. The United States however rejected the threat, saying that its navy would carry on mission in the strait.

Western powers and Israel suspect Iran of seeking to build nuclear weapons. Iran denies this, saying its program is civilian in nature.