Trade powers launched an 11th- hour effort to rescue global trade talks yesterday and the US said it was hopeful of progress.

"Everyone seems focused, which is a good sign," said Seán Spicer, a spokesman for US trade representative Susan Schwab.

Ms Schwab joined counterparts from the EU, Brazil and India to begin five days of closed-door talks on the Doha round of free trade negotiations in Germany.

Representatives of Japan and Australia are due to join them on Saturday.

The fate of the Doha round could depend on whether the so-called G4 group can resolve differences this week on agriculture that have haunted the talks since they were launched more than five years ago in the capital of Qatar.

World Trade Organisation head Pascal Lamy has warned that without a breakthrough very soon, the round could be put on hold for several years.

Negotiators are also set to discuss two other pillars of the talks - services and non-agricultural market access or manufactured goods - which have received less attention due to the insistence of developing countries that a deal to slash rich country farm subsidies and tariffs comes first.

The ministers are meeting in Potsdam, near Berlin.

Washington has demanded that any deal that significantly cuts US farm subsidies must open new export markets around the world in agriculture, manufacturing and services.

Development groups fear the pressure to reach a deal after more than five years of talks could lead to a bad result.

"Poor countries badly need fairer trade rules and an end to trade-distorting subsidies if they are to reduce poverty," said Marita Hutjes, acting head of Oxfam's Make Trade Fair campaign.

"What they don't need is a deal done at any cost, that exposes them to further dumping, and undermines future development prospects."