The authorities said they were investigating a fire that significantly damaged an Islamic center in Missouri on Friday, the first day of fasting in the Muslim holy month of Ramadan, as possible arson.

The Cape Girardeau, Mo., police said they were pursuing leads about the fire, at the Islamic Center of Cape Girardeau.

Shortly before the fire began about 5 a.m., a man was captured on a security camera engaging in “suspicious activity,” according to Norman Baker, a Cape Girardeau Fire Department battalion chief.

He declined to elaborate, but said the fire had been deemed “suspicious in nature” and was being investigated with help from the F.B.I.; the Bureau of Alcohol, Tobacco, Firearms and Explosives; and the Missouri fire marshal.