Armenian officials say an explosion of a city bus in the capital has killed at least one person and wounded six others.

There was no immediate determination of the cause of the Monday evening explosion in Yerevan several kilometers northwest of the capital's central square.

The deputy head of the country's emergencies ministry, Maj.-Gen Nikolai Grigoryan, was cited by the Tass news agency as saying one person had died and six were injured.

Armenian news websites showed photos of a gutted bus with its windows shattered.