NEW YORK: Federal prosecutors Thursday took steps to seize four US mosques and a Fifth Avenue skyscraper owned by a nonprofit Muslim organization long suspected of being secretly controlled by the Iranian government.

The Islamic Education Center is seen in Potomac, Md. on Thursday, Nov. 12, 2009. The center rents this building from the Alavi Foundation, which owns the building but does not run the center. Federal prosecutors filed a complaint Thursday seeking to seize the assets of the foundation. [Agencies]?

The assets include Islamic centers in New York City, Maryland, California and Houston, more than 100 acres in Virginia, and a 36-story office tower in New York.

Seizing the properties would be a sharp blow against Iran, which has been accused by the US government of bankrolling terrorism and seeking a nuclear bomb.

A telephone call and e-mail to Iran's UN Mission seeking comment were not immediately answered.

It is extremely rare for US law enforcement authorities to seize a house of worship, a step fraught with questions about the First Amendment right to freedom of religion.

The action against the Shiite Muslim mosques is sure to inflame relations between the US government and American Muslims, many of whom are fearful of a backlash after last week's Fort Hood shooting rampage, blamed on a Muslim American soldier.

There were no raids Thursday as part of the forfeiture action. The government is simply required to post notices of the civil complaint on the property.

Prosecutors said the Alavi Foundation, through a front company known as Assa Corp., illegally funneled millions in rental income back to Iran's state-owned Bank Melli. Bank Melli has been accused by a US Treasury official of providing support for Iran's nuclear program, and it is illegal in the United States to do business with the bank.

Government officials have long suspected the foundation was an arm of the Iranian government; a 97-page complaint details involvement of several top officials in foundation business, including the country's deputy prime minister and ambassadors to the United Nations.

"For two decades, the Alavi Foundation's affairs have been directed by various Iranian officials, including Iranian ambassadors to the United Nations, in violation of a series of American laws," US Attorney Preet Bharara said in a statement.

The skyscraper, known as the Piaget building, was erected in the 1970s under the shah of Iran, who was overthrown in 1979. The tenants include law and investment firms and other businesses.

The sleek, modern building, last valued at $570 million to $650 million in 2007, has served as important source of income for the foundation over the past 36 years. The most recent tax records show the foundation earned $4.5 million from rents in 2007.

Rents collected from the building help fund the centers and other ventures, such as sending imprisoned Muslims in the US educational literature. The foundation has also invested in dozens of mosques around the country and supported Iranian academics at prominent universities.

If federal prosecutors seize the skyscraper, the Alavi Foundation would have almost no way to continue supporting the Islamic centers, which house schools and mosques. That could leave a major void in Shiite communities, and hard feelings toward the FBI.

Legal scholars who specialize in religious liberty issues said they know of only a few cases in US history in which law enforcement authorities have seized a house of worship. Marc Stern, a religious-liberty expert with the American Jewish Congress, called such cases "extremely rare."

The Alavi Foundation is the successor organization to the Pahlavi Foundation, a nonprofit group used by the shah to advance Iran's charitable interests in America. But authorities said its agenda changed after the fall of the shah.

In 2007, the United States accused Bank Melli of providing services to Iran's nuclear and ballistic missile programs and put the bank on its list of companies whose assets must be frozen.

The United States has imposed sanctions against various other Iranian banks and other businesses.