A meeting of top financial officials from around the globe opened Saturday against a backdrop of 3,000 marching protesters, some of whom turned violent, pelting police with stones, bottles and smoke grenades.

Some 3,000 protesters marched on a downtown hotel where the Group of 20 meeting of finance ministers and central bankers opened, but most of the violence appeared to center around a group of about 200 demonstrators dressed in white coveralls with red bandanas tied around their faces.

Police struck out with batons as protesters rushed the barrier in at least two places, and at one site overturned fences and broke through the initial cordon, according to Associated Press reporters who witnessed the incidents.

A number of officers were injured, but only one seriously. Two demonstrators were arrested, and more arrests were expected, Victoria state Chief Commissioner Christine Nixon said. There were no reports of injured protesters.

"They threw missiles and rocks ... anything they could get their hands on they threw it at police and damaged property," she told reporters. "We have not had anything like this, any kind of violent demonstration in the last six years."

The unrest recalled the widespread violence at anti-globalization protests that marred the World Trade Organization's meeting in Seattle in 1999, and a meeting of the World Economic Forum in Melbourne the following year.

Protesters threw brown and red smoke grenades, shrouding the front line area in a pall, and in one place hit police with small stones, large plastic garbage bins and, occasionally, glass bottles. Police stood their ground, sometimes lashing out with batons.

Finance officials from 19 countries and the European Union, plus top officials of the World Bank and International Monetary Fund are at the talks. Formed in 1999, the G-20 includes the Group of Seven advanced industrial countries and the European Union as well as China, Brazil, India, Russia, South Korea and other major economies.

Argentina, Australia, Indonesia, Mexico, Saudi Arabia, South Africa and Turkey fill out the group, which altogether represents about 90 percent of the world's gross national product, 80 percent of the world's trade and two-thirds of its population.

Reform of the IMF, rising interest rates, the Chinese and Japanese currency levels and efforts to economically isolate nuclear-armed North Korea also are likely to come up at the closed-door meetings.

Surging demand for oil and minerals from fast-growing economies China and India have benefited commodity powers such as Australia, while fanning concerns over the emergence of unstable supplies and market distortions.

De Rato told reporters Saturday that governments have no power to affect the value of major currencies and should leave that task to markets.

"The markets are the ones who fix the value of the most important currencies and governments won't be able to affect that," de Rato said.

On Friday, U.S. Deputy Treasury Secretary Robert Kimmitt renewed Washington's call for China to move faster in reforming its currency, the yuan.

"We believe that the Chinese need to accelerate the movement of their exchange rate to reflect underlying market conditions," Kimmitt told reporters.