Discussions on this issue will continue on Friday, he said, hoping that the ministers could come to some form of conclusion by the end of the two-day meeting.

"No decisions were taken yet today. But ministers had an intense discussion whether ISAF (International Security Assistance Force) could play a role in going after the drug laboratories and the precursors," said de Hoop Scheffer.

The defense ministers devoted their first day of a two-day meeting to Afghanistan.

De Hoop Scheffer said the ministers supported the idea of growing the Afghan National Army (ANA) from about 7,000 at present to 130,000. The growth means the alliance needs to spend more money and provide more trainers, he said.

NATO's strategy is to gradually transfer security responsibilities to the Afghans themselves, seeing the strategy as cost-effective in the long term.

The ANA now takes part in 70 percent of the operations of the NATO-led ISAF and leads in 60 percent of its operations, said NATO spokesman James Appathurai on Tuesday.

The ministers also agreed to help provide security for next year's presidential elections. The ISAF commanders have not yet formalized their demands for extra forces for this task, said the NATO chief. But the alliance is ready to play its part as it did in the previous elections. NATO support has already begun since the start of voter registration on Monday.

The NATO chief said a number of countries have offered to beef up their contingents in Afghanistan, without naming those specific countries.

The ministers' informal meeting is overshadowed by comments of British military commander in Afghanistan, Brigadier Mark Carleton-Smith, over the weekend that the war with the Taliban could not be won. While the New York Times on Thursday quoted a draft report of U.S. intelligence agencies as saying that Afghanistan is in a downward spiral and that the Afghan government, plagued by corruption, may not be able to stem the rise of the Taliban.

De Hoop Scheffer, however, chose to be "cautiously optimistic" on Thursday.

"There is no reason, whatsoever, for gloom and doom," he told reporters.

But he admitted that 2008 has been a challenging year both for Afghanistan and ISAF as attacks in Afghanistan and cross-border support from Pakistan for insurgency in Afghanistan were up.

"Seven years after the fall of the Taliban, the challenges remain real. But the progress is just as real. And our commitment to carry this mission through to success ... remains undiminished," he said.