Putin meets Sultan of Oman in Moscow

Meanwhile, Russian President Vladimir Putin met with Oman's Sultan Haitham bin Tariq Al Said on Tuesday at the Kremlin to discuss the ongoing U.S.-Iran nuclear negotiations.

Oman has been mediating indirect talks between Tehran and Washington, aiming to revive a nuclear agreement that limits Iran's nuclear activities.

Kremlin's foreign policy aide said Russia maintains close contact with Iranian officials and offers assistance where possible.

Meanwhile, Iran announced that expert-level talks between Iran and the United States, originally scheduled for Wednesday, have been postponed to Saturday.