WASHINGTON - A trade agreement between the United States and the European Union would increase prosperity and security on both sides of the Atlantic at a time of rising global challenges, US Secretary of State Hillary Clinton said on Thursday.

"If we get this right, an agreement that opens markets and liberalizes trade would shore up our global competitiveness for the next century, creating jobs and generating hundreds of billions of dollars for our economies," Clinton said in a speech at the Brookings Institution.

Clinton's strong endorsement of the proposed pact was the latest indication that the United States and the 27 nations of the European Union could launch talks on a comprehensive trade agreement early next year.

A high-level, US-EU working group led by US Trade Representative Ron Kirk and EU Trade Commissioner Karel De Gucht has been studying the issue for the past year and is expected to formally recommend negotiations in a report to be released in December or January.

The United States and the European Union account for about half the world's economic output and nearly a third of world trade. A deal could increase economic output by 122 billion euros ($158 billion) a year for Europe and add 0.52 percent to the EU's gross domestic product in the long term, according to European Commission estimates.

Beyond the monetary benefits, Clinton argued a trade pact would increase transatlantic security "in the face of rising challenges to our economic model" and the growth of many "behind-the-border" measures that impede trade.

"At a time when countries are measuring their influence as much by the size of their economies, as by the might of their militaries, we have to realize the untapped potential of the transatlantic market. This is as much a strategic imperative, as an economic one," Clinton said.

"There may be no greater threat to our security and our transatlantic partnership than a weak economic future on one or both sides of the Atlantic," Clinton said, that each side has its own work to do at home to restore economic growth.

The United States faces another possible recession unless the White House and Congress reach a deal to stop tax increases and spending cuts that kick in at the end of the year.

Meanwhile, Europe continues to grapple with a three-year-old debt crisis that has crippled economic growth.

Clinton, who is in her final months as Secretary of State, emphasized a final decision to launch talks has not been made, noting the United States is looking for progress from the EU on "longstanding barriers to trade and market access".

She did not elaborate, but US farm groups continue to be frustrated by a number of European barriers to their products.

This month, a coalition of 60 US food and agricultural groups expressed concern that their issues would not be addressed in the proposed trade agreement.