A microwave oven sparked a fire Wednesday morning at a high-rise hotel in the River North neighborhood.

A small fire broke out in a room on the 18th floor of the Residence Inn at 410 N. Dearborn St., according to Fire Media Affairs. It was discovered by hotel staff and put out with fire extinguishers.

The origin of the fire is thought to be a microwave, according to Fire Media.

The Office of Fire Investigation will make the final determination of the cause.