LONDON -- British police are searching for two young men suspected of releasing an irritating gas on a London subway train.

Authorities said paramedics treated a number of people for coughing and shortness of breath when the train stopped at Oxford Circus station.

British Transport Police say the victims' symptoms suggested they had been exposed to CS gas, a component of tear gas that U.K. police forces carry to incapacitate suspects.

They said there were no indications the subway incident caused serious health issues.

Police released closed-circuit TV images of two suspects and asked the public for help identifying them.