BRUSSELS, March 29: Afghanistan's neighbours are drawing up a plan to tackle the flow of heroin from the world's top producer of opium poppy into Russia and Europe , the U.S. State Department's Afghan coordinator said on Monday.

The Central Asian nations' initiative, which will complement a drive by Kabul to destroy poppy fields and heroin factories, is likely to be signed at an international conference on Afghanistan, which opens in Berlin on Wednesday.

"Neighbours have both a responsibility and a concern that opium poppy and opium and heroin are leaking through their countries," William Taylor told a video-linked news conference from Berlin. "If the neighbours can join together and begin to shut off that flow this will be an important commitment."

Diplomats say, however, that persuading some of these countries to put action behind a written commitment may be difficult as the heroin trade is a hugely lucrative business.

Tajikistan, Uzbekistan, Turkmenistan and Iran are the main transit states for opiates from Afghanistan, whose output has soared since the 2001 ouster of the Taliban.

The Taliban had almost eradicated opium production during their final year in power. But output has since taken off and - according to U.N. estimates - last year reached 3,600 tons, more than three-quarters of global supply.

Five of Afghanistan's six neighbours participate in "Operation Topaz", an International Narcotics Control Board monitoring operation to track the flow of acetic anhydride, a key chemical used in the manufacture of heroin.

Turkmenistan, which shares a 700-km border with Afghanistan, has not joined the operation. It was criticized by the United Nations this month for not cooperating.

Taylor gave no details of the coordination plan, but said Washington would provide some 40 million dollars over two years to support the establishment of special Afghan police units that, starting next month, would start to eradicate opium poppy fields before they were harvested.

"What needs to happen...is a signal to farmers and others that growing poppy is illegal and the law that makes it illegal will be enforced," he said. "There is going to be for the first time some risk associated with growing poppy in Afghanistan."

NATO has come under fire from some non-governmental organizations for not using its 6,300-strong peacekeeping force in Afghanistan to tackle poppy cultivation and trade.

U.S.-led troops have been instructed to destroy opium stockpiles or heroin laboratories if they come across them, arrest traffickers or tip off Afghan authorities. "We've suggested that NATO...take a look at that as a model," Taylor said. -Reuters