WASHINGTON—The U.S. handed down a fresh set of sanctions on the Iranian government Monday in the latest bid to pressure Tehran to end its nuclear program.

The White House announced Monday it was freezing all property owned in the U.S. by Iran or the Central Bank of Iran. President Barack Obama, in an executive order signed Sunday, said the Central Bank of Iran was concealing transactions of sanctioned parties and that Iran was not making progress in halting money laundering.

The U.S. Treasury Department, which is responsible for enforcing sanctions, said in a statement Monday that "Iran now faces an unprecedented level of pressure" and that the new sanctions confirms Iran "will face ever-increasing economic and diplomatic pressure until it addresses the international community's well-founded and well-documented concerns regarding the nature of its nuclear program."

Western governments are trying to tighten the screws on Iran amid growing concern that the country is trying to develop nuclear weapons. Iran has said that its nuclear program is for peaceful means.

The U.S. is already implementing sanctions that aim to cut off Iranian oil exports, a major source of revenue for Iran's government. Top U.S. officials recently met with Japanese and Chinese leaders, who are being asked to cut off Iranian crude oil imports.