Police took two fans attending the European championship into custody following a disturbance in Lisbon's central Rossio square, a spokeswoman said. One was released.

"The other will appear in court tomorrow on charges," she said. She had no further details.

The incident took place when Rossio square was crowded with tourists, fans and people attending a religious festival.

TSF radio reported that English fans threw bottles at a bus carrying festival participants and sprayed gas into it. Police said one English fan was taken away for questioning and then released.

Police took four other English fans into custody on Saturday morning in Lisbon and two were released, the embassy spokeswoman said. The others were fined for creating a disturbance.

England play France at 1845 GMT on Sunday in Lisbon. The game is the tournament opener for the Group B teams and organisers say it carries a high risk of violence.

England fans rioted at the European Championship in Belgium and the Netherlands in 2000 and European soccer's ruling body has warned England they will be expelled from this tournament if there is a repeat.