Anti-globalization protesters fought pitched battles with Hong Kong police on Saturday outside a convention center where trade ministers from around the world were making a last-ditch effort to rescue a global pact.

Witnesses said hundreds of protesters from South Korean farmers' groups, who say free trade is ruining them, broke through police lines to reach the building, although they were prevented from getting inside.

"It is a stand-off at the building. Fifty riot police just rushed inside the building. They are not allowing anyone out," said one Reuters reporter at the scene.

Smoke could be seen rising from an area near the convention center where the World Trade Organization (WTO) meeting is underway and policemen could be seen preparing to use tear gas, another Reuters reporter said.

The violence had no immediate impact on the negotiations inside, where ministers from some 150 states were struggling to reach some minimal accords.

Diplomats said a failure to resolve the sticking points before talks end on Sunday would reduce the chances of a deal next year freeing up global business in farm and industrial goods and services.

"Either everything will unravel and we will have another Cancun situation -- I hope it won't happen -- or we'll have lowered ambitions in the meeting in Hong Kong," Kenyan Trade Minister Mukhisa Kituyi told Reuters in an interview.

Kituyi, who has mediated on agricultural issues at the talks in Hong Kong since they got underway on Monday, was referring to the acrimonious collapse of negotiations on the so-called Doha trade round at a WTO meeting in Cancun, Mexico, two years ago.

The United States put a brave face on the struggling talks.

"As we approach the final 24 hours of the negotiations, we have a very large opportunity to put together an outcome that would be extremely positive for development ... it is just beyond our fingertips," said Deputy Trade Representative Peter Allgeier.

Outside, protesters stormed heavily-fortified police lines, breaking through the front ranks as riot police used pepper spray, batons and fire hoses to try to beat them back.

Groups of protesters were also seen running down sidestreets close to the convention center trying to outflank police lines.

Several tried to push over two police cars.

More than 20 protesters had been injured by pepper spray, witnesses said, and radio station RTHK reported at least one policeman had been injured.

A draft of the 149-nation organization's final declaration, released after negotiators worked through the night in a private "green room", showed there was still no agreement on setting a date for ending farm export subsidies.

The European Union has balked at fixing a date because, it says, the United States, Australia, Canada and New Zealand must agree to reforms of their farm export systems first.

The draft suggested a date of 2010 for the elimination of the subsidies or within a period of five years but both suggestions were inside brackets, meaning neither may be adopted in the end.

"It's a sad day when we're getting excited about an end-date in brackets," said Bob Stallman, head of the United States' biggest farm group, the American Farm Bureau Federation.

One diplomat said representatives of EU member states were told by negotiators from the bloc's Executive Commission that they might have to agree later on Saturday to a subsidies cut-off date or risk being blamed for a collapse of the WTO round.
The draft declaration also showed that there had been no headway made on a plan to give duty-free and quota-free access to exports from the world's least-developed countries (LDCs).

The United States has reservations about this initiative because it wants to exclude some goods, including textiles from Bangladesh and Cambodia.

"If nothing is agreed on the LDC package it will give a very wrong message that the negotiators have been so self-centered that they have forgotten the weakest part of the international community," Anwarul Chowdhury, U.N. Undersecretary General for LDCs, told a news conference.

Nevertheless, Brazilian Foreign Minister Celso Amorim, whose country is a key figure in the G20 developing country alliance, said there were some grounds for hope.

"It's modest. It's much below what we had expected but in any case at least we are starting to move," Amorim told reporters.

Supporters of the Doha trade deal say it could inject zest into the global economy and lift millions out of poverty, but detractors say it will only bring more profits for rich nations and their companies at the expense of the developing world.

The WTO needs a blueprint for concluding the Doha round within the first few months of 2006 if it is to have any hope of finalizing a treaty by the end of the year.