France's prime minister wants a rate cut to weaken the euro

The decision comes despite the strength of the euro, which set a new record high against the US dollar of $1.4284 on Monday.

The ECB's policymakers were meeting in Vienna in one of their twice-yearly meetings away from Frankfurt.

At a news conference, ECB President Jean-Claude Trichet said that there is "heightened uncertainty" about the outlook for Europe's economy.

As last month, he added that the ECB would continue to "monitor very closely all developments" in the euro zone.

The French president, Nicolas Sarkozy, has put pressure on the ECB to cut rates in order to reduce the value of the euro and boost European competitiveness.

The strong euro makes European exports more expensive to customers outside the euro zone.

Mr Trichet would not be drawn on currency questions, saying that "verbal discipline is very important" where currencies are concerned and stressing that the methodology is in place to deal with volatility.

Before the credit crunch hit global markets in the summer, the ECB had been expected to raise rates to 4.5% by the end of the year, but the consensus is now for them to remain unchanged in November and December.