ECB's Trichet flags rate increase with 'vigilance'

European Central Bank President Jean- Claude Trichet signalled the ECB will likely raise interest rates next month as the pace of economic growth threatens to stoke inflation.

``Strong vigilance remains of the essence so as to ensure that risks to price stability over the medium term do not materialize,'' Trichet said at a press conference in Frankfurt. The ECB left its key lending rate at 3.5 percent at its meeting Thursday.

In his statement, Trichet also said that 'acting in a firm and timely