Prime Minister Gordon Brown said Wednesday that Taliban fighters in Afghanistan can win a role in the country's future if they renounce violence, and he pledged a long-term British troop presence.

Brown told lawmakers that Britain would support efforts by Afghan President Hamid Karzai to bring former insurgents into mainstream politics.

"If they are prepared to renounce violence and abide by the constitution and respect basic human rights then there is a place for them in the legitimate society and economy of Afghanistan," Brown told the House of Commons.

He said Britain would not hold direct talks with ex-Taliban fighters, but would support the attempts by Karzai's officials to widen Afghanistan's political sphere.

"Iran, too, must start to play a more constructive role," Brown said, telling lawmakers military action must be supported by work on political reconciliation, including from Afghanistan's neighbors.

Brown's comments came days after Afghan, British and U.S. forces retook a southern Afghan town from the Taliban. Taliban militants overran the town of Musa Qala in February, four months after British troops left following a contentious peace agreement that gave security responsibilities to Afghan elders. U.S. officials criticized the deal as surrendering to the Taliban.

Britain is helping to identify members of the Taliban — particularly midlevel commanders — who are prepared to participate in mainstream politics, a senior government official told reporters. He spoke on condition of anonymity in line with government policy.

"It is not a question of negotiating with the Taliban, it's a question of splitting the Taliban," he said.

Officials said Afghan-led reconciliation efforts are focused on middle- and lower-ranking Taliban fighters.

"Already some 5,000 fighters have laid down their arms," Brown said. British officials said 70 high- or middle-ranking Taliban leaders have been killed this year.

Britain believes around 10 to 12 people are coordinating the Taliban insurgency, meeting in Pakistan's tribal areas and in the city of Quetta, the official said.

"These are people we would like to see arrested," he said. "They don't spend much time in Afghanistan."

Brown said Britain will keep around 7,800 troops in Afghanistan for the long term, without specifying a limit on how long soldiers could remain.

Some British military chiefs have suggested troops will be required for decades.

Brown's office said he would not set a timetable for changing troop numbers, and that Britain will stay in Afghanistan until it achieves security.

But Brown told lawmakers a rising number of newly trained Afghan soldiers — expected to reach 70,000 next year — as well as EU and NATO allies must do more to share the security burden.

Brown said new commitments from Denmark, France, Germany and others were welcome. "This progress must, I believe, now be matched by contributions from other counties in NATO, the EU and beyond," he said.

Officials said the Afghan National Army will not operate autonomously until 2012.

Brown said Britain has pledged $920 million in development aid from 2009 to 2012, aiming to strengthen Afghanistan's legal processes.

He offered no new plans to tackle the country's booming narcotics trade. Officials said Britain opposes aerial spraying of poppy fields and a plan to buy farmers' crops so they can be destroyed, or used for medicinal purposes.

Figures released in July showed Afghanistan's illicit heroin-producing poppy harvest set another record this growing season.