The United States announced on Friday to freeze the assets of four Iranian companies who are accused by the United States of getting involved in Iran's proliferation of weapons of mass destruction.

The four companies are Pars Tarash, Farayand Technique, Fajr Industries Group, and Mizan Machine Manufacturing Group, according to a statement by the U.S. Treasury Department.

"So long as Iran continues to pursue a nuclear program in defiance of the international community's calls to halt enrichment, we will continue to hold those responsible to account for their conduct," said Stuart Levey, U.S. under secretary of treasury for terrorism and financial intelligence.

Iran, branded by the United States as one of the "state sponsors of terrorism," has been under UN sanctions for its defiance over its nuclear program.

The United States has accused Iran of trying to develop nuclear weapons under the cover of a civilian nuclear program. However, Iran has said its nuclear program is for peaceful purposes only.

Source: Xinhua