UNITED NATIONS — Russia's ambassador to the UN has responded cautiously to U.S. allegations that Iran tried to kill Saudi Arabia's ambassador in Washington.

"I'm not an expert, but we're going to look at it very, very seriously," Vitaly Churkin told reporters late last week. "We have sent all the information received to Moscow. There will be contacts, and they'll look at it very seriously."

China's deputy ambassador, Wang Min, said only, "They're still investigating, right?"

But U.S. allies on the UN Security Council said U.S. Ambassador Susan Rice had presented "very credible and very convincing" evidence about the involvement of Iranian officials — but left unanswered the question of whether Iran's top political and religious leaders knew about the plot.

Washington wants to use the alleged plot as a springboard for increased international condemnation of Iran and, perhaps, for new sanctions.

A U.S. criminal complaint accused two Iranians of hiring a would-be assassin in Mexico — who also was a paid informant for the U.S. Drug Enforcement Administration. A 56-year-old U.S. citizen who also holds an Iranian passport has been arrested. A suspected member of the elite Quds Force is still at large.

Russia Cautious on Iran 'Murder Plot'