U.S. President Barack Obama says turmoil will continue to grip the world's financial markets unless European leaders take decisive action.

Mr. Obama issued the warning during a joint news conference Wednesday with Australian Prime Minister Julia Gillard in Canberra.

Mr. Obama said European leaders need to put in place a “concrete plan” to show financial markets they will back the euro despite concerns sparked by the current debt crisis. He said the U.S. is closely consulting with European officials and praised what he called the “genuine desire” of leaders like French President Nicolas Sarkozy and German Chancellor Angela Merkel to solve the crisis.

Still, the U.S. president said the main problem facing the eurozone is a “problem of political will,” adding that he remains deeply concerned about the impact the debt crisis is having on the world economy.

Mr. Obama's comments come one day after U.S. Treasury Secretary Timothy Geithner told an event in Washington sponsored by the Wall Street Journal that European officials need to take action “so they don't continually fall behind the curve of the market.”

Geithner also said he believed the Europe Union is making gradual progress and that a solution is still within reach.

Fears the European financial crisis is about to get worse sent Japan's Nikkei and Hong Kong's Hang Seng indexes lower in Wednesday's early trading.