Investigators are looking for evidence of arson after a mosque in southwest Missouri was burned to the ground in the second fire to hit the Islamic centre in little more than a month.
No injuries were reported in the fire on Monday, but the Islamic Society of Joplin's building was destroyed in the blaze, first reported at about 3:30am, the Jasper County Sheriff's Office said.
Investigators from the FBI, the Bureau of Alcohol Tobacco and Firearms and the Jasper County Sheriff's department were at the scene all day, moving the rubble with a bulldozer and other equipment.
Meanwhile, a small group of Muslims gathered for evening prayer on the lawn of the destroyed building.
It was the second time this summer that investigators had been called to the Islamic centre, located in a former church on the outskirts of Joplin.
A fire reported around the same time on July 4 has been determined to be arson, but no charges have been filed.
The FBI has released a video of a suspect caught on surveillance video and offered a $15,000 reward for information leading to an arrest in that fire.
'Sad and shocked'
Michael Kaste, special agent in charge of the Kansas City office of the FBI, said the investigation into Monday's fire was in the preliminary stages, and that about 30 people had been assigned to the investigation.
Imam Lahmuddin, who leads the mosque and was in the building until late Sunday, said he was "sad and shocked" about the fire.
"Maybe there is something we are supposed to learn from this," he said.
A Washington-based Muslim civil rights organisation meanwhile called for more police protection at mosques and other houses of worship following the Joplin fire and a deadly attack at a Sikh temple in Wisconsin on Sunday.
The Council on American-Islamic Relations also offered a $10,000 reward for information leading to the arrest and conviction of whoever started the mosque fire.
About 50 families belong to the Islamic Society of Joplin, which opened in 2007 as a mosque and community centre.
The FBI led an investigation in 2008 when the mosque's sign was torched. That crime also remained unsolved.
Nobody has yet been arrested in connection with Monday's fire.