The New York Times last week reported that Washington used back-door channels to warn Iranian Supreme Leader Ali Khamenei that closing the key strait was a "red line" that, if crossed, could be met with a harsh response.
Ramin Mehmanparast, a spokesman for the Iranian Foreign Ministry, said the Iranian government received the message through three diplomatic channels. He said Susan Rice, the U.S. ambassador to the United Nations, delivered the message to her Iranian counterpart, the Swiss ambassador to Iran and Iraqi President Jalal Talabani, Iran's state-funded broadcaster Press TV reports.
The government, he said, was studying the letter and "will respond if necessary."
Mehmanparast said in December, before Iran conducted war games near the strait, that Western countries wouldn't "sacrifice their national interests for the political objectives of the U.S. and a limited number of Western allies."
The U.S. Navy 5th Fleet is based in the Persian Gulf across from Iran in the Sunni-led monarchy of Bahrain.
Dennis Ross, a former national security adviser for U.S. President Barack Obama and Secretary of State Hillary Clinton's former point man on Iran, told Bloomberg News last week there were "all sorts of local triggers for conflict" in the Persian Gulf.