Although official details are sketchey, it is understood that CS gas was used by West Mercia Police at Foregate Street Railway Station, Worcester earlier.
The incident involved football supporters.
Update 10pm:
The incident involving the use of CS gas happened when Hereford United supporters were returning from this afternoon's game at Kidderminster. The train they were on arrived at Foregate Street to be met by a large police presence.
For reasons yet to be confirmed CS was directed towards some fans.
BBC Hereford and Worcester are expected to have a report about the incident on tomorrow morning's news.