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

In what could prove to be one of the biggest counterterrorism seizures in U.S. history, prosecutors filed a civil complaint in federal court seeking the forfeiture of more than $500 million in assets of the Alavi Foundation and an alleged front company.

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 U.S. government of bankrolling terrorism and seeking a nuclear bomb.

It is extremely rare for U.S. 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 U.S. 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 U.S. 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,” U.S. Attorney Preet Bharara said in a statement.

(Source: NBC New York)