FARMINGTON — Police are investigating a robbery and assault late Sunday at Irving/Circle K at 309 Main St.

An undisclosed amount of cash was stolen from the register, Police Chief Kenneth Charles wrote in a media statement Monday. The clerk was assaulted but refused medical attention, he said.

The male suspect, described as about 6 feet tall and wearing a black face mask, fled on foot. No weapons were displayed or used during the robbery, which was reported at 11:12 p.m., the chief said.

Wilton police and the Franklin County Sheriff’s Office responded to assist, along with a police K-9.

The investigation is ongoing and details will be made available as they develop, Charles said.

Anyone with information about the robbery is asked asked to call the Farmington Police Department at 207-778-6311.