(Reuters) - A large gas explosion killed one person and injured eight others in Canton, central Illinois on Wednesday, officials said on social media, as rescue workers searched for more casualties as night fell on the small town.

"This is a very slow and methodical process. They are working hard and as fast as possible," the Fulton County Emergency Services and Disaster Agency said on Facebook.

The explosion occurred at 5:45 p.m. near the main square in the town of 15,000 people, the agency said.

The condition of the injured was unclear as agency officials were not immediately available for comment.

(Reporting by Brendan O'Brien in Milwaukee; Editing by Simon Cameron-Moore)