After over a week of saying the dollar has fallen too far recently, International Monetary Fund (IMF) chief Rodrigo de Rato warned Monday that there are still risks of an "abrupt fall" in the dollar.

"There are risks that an abrupt fall in the dollar could either be triggered by, or itself trigger, a loss of confidence in dollar assets," Rato told the IMF board of governors.

"And there is a risk that exchange rate appreciation in countries with flexible exchange rates -- including the euro area -- could hurt their growth prospects, and that in these circumstances protectionist pressures could worsen," he added.

In its twice-yearly World Economic Outlook published Wednesday, the IMF lowered its 2008 global economic growth forecast to 4.8 percent from 5.2 percent it estimated in July due to the financial turmoil.

Citing the crisis, Rato also said the world economy now was at "a time of uncertainty," instead of a time of opportunity it was in spring.

"Over the past few months, we have lived through an earthquake in the credit markets," he said. "Like most earthquakes, it has been distant for most people: something they have read about in the newspapers."

"But there is still a risk of aftershocks, and the full effects of the disruption we have already had will only be felt over time. We need to consider what actions we can take to limit the damage, and also what lessons we can learn from the crisis," he said.