US forces struck Iran's three main nuclear sites, Trump said late on Saturday, and he warned Tehran it would face more devastating attacks if it does not agree to peace.

"Trump, who came in as a peacemaker president, has started a new war for the US," Medvedev wrote on his Telegram channel, adding that "with this kind of success, Trump won't win the Nobel Peace Prize".

The leader of Russia's Liberal Democratic Party Leonid Slutsky said the strikes "had no military reason for the US and cannot be justified under international law".

"The consequences of the escalation threaten to go beyond the region. Washington understands the inevitability of Tehran's response. All this brings the spiral of confrontation to a new level and increases the risks of World War III," Slutsky, who heads the State Duma international affairs committee, wrote on Telegram.

--Reuters--