Moscow: A senior Russian diplomat on Thursday strongly warned the West against an attack on Iran, saying that it would upset global security.

Deputy Foreign Minister Sergei Ryabkov told the news agency that a military action against Iran would be a "grave mistake, a flagrant error" with far-reaching consequences for regional and global stability. "It could shake the foundations of the international system," he said.

Ryabkov also said Russia is firmly against any new sanctions on Iran, adding that they wouldn't help nuclear non-proliferation. He said unilateral sanctions by some Western powers will hurt efforts to settle the Iranian nuclear standoff through talks.

Russia has long mixed careful criticism of Iran, an important trading partner, with praise for some of its moves and calls for more talks.

Ryabkov's comments followed Wednesday's Russian Foreign Ministry statement that expressed regret and concern about the launch of work at a new Iranian uranium enrichment facility, but urged all parties involved in the nuclear standoff with Tehran to avoid hasty moves.

Iran insists its uranium enrichment programme is aimed at civilian power generation and research, but Western nations believe it is a cover for a nuclear weapons bid.

Moscow, which built Iran's first nuclear power plant, backed some of the previous UN sanctions against Iran, but in recent months has firmly rejected imposing any new sanctions and called for dialogue.

Iran has responded to the Western pressure with threats and posturing. A senior commander of the Revolutionary Guard force was recently quoted as saying Tehran's leadership has decided to order the closure of the Strait of Hormuz, a strategic oil route, if the country's petroleum exports are blocked.

Ryabkov referred to the threats, saying that the Strait of Hormuz must remain free for shipping, but adding that Iran has the right to ensure its security and conduct maneuvers in the area.

He urged both Iran and the West to "avoid statements and actions that could lead to further escalation of confrontation."

He also said Russia was trying to encourage other parties to continue six-way international talks to settle the Iranian nuclear standoff.

"We must double our efforts to resume talks," he said.