Shots have been fired at a branch of American Express in the Greek capital, Athens, by two gunmen on a motorbike.

Police said the attack broke windows but caused no injuries.

The leftist urban guerrilla group called the Revolutionary Organisation Red Line claimed responsibility for the attack.

There have been several bomb attacks in the capital during the past month, most of them apparently in protest at NATO's air strikes against Yugoslavia. A powerful explosion damaged the garage of the Dutch embassy in Athens yesterday.