DAVOS, Switzerland, (AP) -The world’s top commercial powers on Saturday make their first joint attempt at reviving global trade talks since their collapse last summer, but the chance of real progress being achieved in the Swiss Alps appears unlikely.

Representatives of the United States, the European Union, India, Brazil and about two dozen other countries are meeting on the sidelines of the World Economic Forum, six months after they acrimoniously failed to reach a breakthrough on clearing barriers to trade in farm goods and manufactured products.

Although a pledge of commitment is expected from all sides, little is foreseen in terms of negotiating action and World Trade Organization officials already have played down the meeting.

The return to talks comes amid increased support from global business leaders and top politicians and the WTO negotiations have been the subject of repeated discussions during the first three days of the Forum.

Brazilian President Luiz Inacio Lula da Silva and British Prime Minister Tony Blair pleaded Friday for progress, a day after 65 of the most powerful business executives warned that failure to reach a new trade deal would undermine the world’s economic growth and risk the dangers of protectionism.

“If it succeeds, great. If it fails, it will be catastrophic,” Blair said of the so-called Doha round of trade talks.

But while pledges of commitment have never lacked, getting countries to open up their markets to foreign competition has been much more difficult since the round’s inception in Qatar’s capital five years ago.

There have been notable clashes over the farm subsidies and tariffs in rich countries that poorer nations say are preventing them from developing their economies. The nearly incessant sniping between the 27-nation EU and the U.S. also has repeatedly stalled the round.

Summits in Cancun, Mexico, in 2003 and in Hong Kong just over a year ago both failed to outline concrete steps for liberalizing the global economy and were more noteworthy for the public bickering among ministers and the angry street protests they sparked.

The frustration ultimately reached boiling point in July when the WTO’s director-general, Pascal Lamy, called for a halt to talks after the organization’s most powerful members refused to budge from entrenched positions on farm support and manufacturing tariffs.

Although talks were never formally or legally suspended, Lamy has said that he will only “officially restart” the round when countries signal their readiness to make concessions.

The positive note he has sounded out in recent weeks has raised speculation that he may make the announcement Saturday in Davos, but even that would be little more than symbolic and meant primarily to kickstart a final push for a deal.

Negotiators are trying to forge the blueprint of an accord before July, when President Bush’s authority to make trade deals that can be sent to Congress for a simple yes-or-no vote expires.

Without the so-called “fast track” authority, it would be much harder for any treaty to gain congressional approval in the U.S., the world’s largest trading nation.