Some departments at the U.S. embassy in the Indian capital New Delhi will shut for a day on Thursday due to security concerns, an embassy statement said. The announcement came days after the United States put New York, Washington and other financial centres in the United States on a high alert for attack and stepped up security. "In light of security concerns, the Consular Section and the Department of Homeland Security -- Immigration Office ... and the Information Resource Center (American Library) ... will close to the public on Thursday, August 5, 2004," the statement said. It gave no details of the security concerns but added that U.S. consulates in the other Indian cities of Bombay, Madras and Calcutta would stay open for business as usual. The embassy said it would work to continue to provide emergency services to American citizens during the one-day suspension in New Delhi. It also urged Americans in India who have not registered with the embassy to do so as soon as possible. Attacks have targeted U.S. missions in India in the past. Security has been beefed up at all missions since the Sept. 11, 2001, attacks in the United States. Gunmen shot dead four Indian police guards outside the U.S. cultural centre in the eastern city of Calcutta in early 2002.