Gunmen attacked the American Center Library in India's eastern city, Kolkata, also known as Calcutta, Tuesday killing five guards and wounding at least 16 others. Two militant Islamic groups are claiming responsibility for the attack.

Gunmen on two motorcycles opened fire at a police checkpoint guarding the American center at dawn Tuesday, shooting guards and pedestrians before speeding away. The American Center houses a large library, cultural center and the U.S. Consulate's public affairs section.

Rex Moser, a spokesman for the U.S. Consulate, says the American Center and the consulate have been closed temporarily. "Clearly," Mr. Moser said, "we have to reassess our security situation as to what we can and cannot do. It is really to early to say how this will affect us other than the fact that both the American Center and the American Consulate in Calcutta are closed."

Authorities say two Islamic Militant groups have claimed responsibility for the attack, which took place as U.S. Federal Bureau of Investigation Director Robert Mueller is visiting New Delhi to discuss counterterrorism cooperation with Indian officials.