Iranian Unit to Be Labeled 'Terrorist'

The United States took punitive action against Iran after the November 1979 takeover of the U.S. Embassy in Tehran, including the breaking of diplomatic ties and the freezing of Iranian assets in the United States. More recently, dozens of international banks and financial institutions reduced or eliminated their business with Iran after a quiet campaign by the Treasury Department and State Department aimed at limiting Tehran's access to the international financial system. Over the past year, two U.N. resolutions have targeted the assets and movements of 28 people -- including some Revolutionary Guard members -- linked to Iran's nuclear program.

The key obstacle to stronger international pressure against Tehran has been China, Iran's largest trading partner. After the Iranian government refused to comply with two U.N. Security Council resolutions dealing with its nuclear program, Beijing balked at a U.S. proposal for a resolution that would have sanctioned the Revolutionary Guard, U.S. officials said.

China's actions reverse a cycle during which Russia was the most reluctant among the veto-wielding members of the Security Council. "China used to hide behind Russia, but Russia is now hiding behind China," said a U.S. official familiar with negotiations.

The administration's move comes amid growing support in Congress for the Iran Counter-Proliferation Act, which was introduced in the Senate by Gordon Smith (R-Ore.) and in the House by Tom Lantos (D-Calif.). The bill already has the support of 323 House members.

The administration's move could hurt diplomatic efforts, some analysts said. "It would greatly complicate our efforts to solve the nuclear issue," said Joseph Cirincione, a nuclear proliferation expert at the Center for American Progress. "It would tie an end to Iran's nuclear program to an end to its support of allies in Hezbollah and Hamas. The only way you could get a nuclear deal is as part of a grand bargain, which at this point is completely out of reach."

Such sanctions can work only alongside diplomatic efforts, Cirincione added.

"Sanctions can serve as a prod, but they have very rarely forced a country to capitulate or collapse," he said. "All of us want to back Iran into a corner, but we want to give them a way out, too. [The designation] will convince many in Iran's elite that there's no point in talking with us and that the only thing that will satisfy us is regime change."

Staff researcher Madonna Lebling contributed to this report.