The U.S., British and Canadian governments tightened international sanctions on Iranian government officials, including those tied to the crackdown on anti-government protesters following contested presidential elections in 2009.
"The message to the Iranian government from the U.K. and its partners is clear," said British Foreign Secretary William Hague in a statement. "It needs to change its behavior before it will be treated as a normal member of the international community."
Western governments accuse Iran of using a civilian nuclear program to cover illicit weapons activity. Tehran denies the charges.
U.S. Navy Adm. Mike Mullen, chairman of the Joint Chiefs of Staff, accused Iran at a Pentagon press luncheon of arming Shiite rebels in Iraq.
"Iran is playing an outside role right now," he told reporters. "Iran is very directly supporting extremist Shiite groups (that) are killing our troops."
Tehran, for its part, targeted several top U.S. officials, including former Defense Secretary Donald Rumsfeld, with unspecified sanctions. It later asked U.S. President Barack Obama to take legal action against former U.S. President George W. Bush and former British Prime Minister Tony Blair.