Workers on London's Underground rail system are to stage six days of strikes in a dispute over the sacking of two train drivers, the RMT union said on Wednesday.

The strikes will be held this month and in June over the dismissals of two men who, the RMT said, were fired because of union activities.

The first strike will start on the evening of May 16 and run into May 17, the RMT said.

Transport for London (TFL), responsible for the capital's underground system, has said one of the drivers was dismissed because of a breach of safety rules, while the other had been sacked for being abusive to colleagues.

Reuters