The upcoming Group of 20 summit must focus on growth to keep global economic recovery stay on track, according to U.S. Treasury Secretary Timothy Geithner on Saturday.

"This summit must be fundamentally about growth, and our challenge as the G20 is to act together to strengthen the prospects for growth," Geithner said during a press briefing held in Toronto before the G20 summit opening.

He said that the world economy is now coming out of the fires of the crisis because of the cooperation among the G20.

"The world economy is now growing again, trade is expanding, and we are repairing the financial damage," Geithner said.

He noted that thanks to cooperation, there are already some constructive outcomes achieved before the summit.

"Just in the past few weeks, we've made very important additional steps forward," he said.

The United States is on the verge of enacting the strongest set of reforms -- financial reforms -- since those that followed the Great Depression.

The leaders of Europe have acted to establish a powerful financial stability program to stand behind their members that are undertaking reforms to address their financial challenges. And Europe is now moving to bring greater transparency and a stronger financial foundation to its banking system.

China is acting to further reform its exchange rate.

But he warned that the world economy remains fragile.

"The scars of this crisis are still with us," he said.

Geithner said that "what we share in the G20 is a recognition that if the world economy is to expand at its potential, if growth is going to be sustainable in the future, then we need to act together to strengthen the recovery and finish the job of repairing the damage of this crisis."