In what could be one of the biggest counterterrorism seizures in US history, federal prosecutors sought to take over four US mosques and a New York City skyscraper owned by a Muslim organization suspected of being controlled by the Iranian government. Prosecutors filed Thursday a civil complaint in federal court against the Alavi Foundation, seeking the forfeiture of more than $500 million in assets. The assets include bank accounts; Islamic centers consisting of schools and mosques in New York, Maryland, California and Houston; more than 100 acres in Virginia; and a 36-story Manhattan office tower. Confiscating the properties would be a sharp blow against Iran. A telephone call and e-mail to Iran's UN Mission seeking comment were not immediately answered. John D. Winter, the Alavi Foundation's lawyer, said it intends to litigate the case and prevail. He said the foundation has been cooperating with the government's investigation for the better part of a year. “Obviously the foundation is disappointed that the government has decided to bring this action,” Winter said. 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 mosques is sure to inflame relations between the US government and American Muslims.