US Afghan surge is working: UN envoy

US Afghan surge is working: UN envoy Washington: The US-led surge of troops in Afghanistan is proving successful with the Taliban on the defensive despite persistent bloodshed, the United Nations envoy to the country has said.

The assessment by Staffan de Mistura, the UN special representative in Kabul, contrasts with weariness among the public in the United States about the country's longest war which will reach the 10-year mark later this year.

General David Petraeus leads about 100,000 US troops in Afghanistan, part of a strategy laid out in December 2009 by President Barack Obama to scale up the war launched after the September 11, 2001 attacks.

"The fact is that the surge by General Petraeus... is working," de Mistura said at the Middle East Institute, a Washington think-tank.

De Mistura, a friend of Petraeus since they served together in Iraq, acknowledged that violence in Afghanistan "looks very bad." But he said the Taliban were attacking away from areas where they were under pressure -- and alienating Afghans through indiscriminate killings.

"These are mistakes produced by the feeling that there is a need to produce a counter-narrative to the reversal of the momentum" of the Taliban, de Mistura said.

De Mistura said it would be critical to see if the Taliban are able to regroup with the arrival of spring and launch an offensive.

But it is even more important to make progress this year on negotiating a political solution, he said.

"The military aspect alone cannot be an indicator of any sustainable success because we have all agreed -- everyone, and in my opinion, even the Talibans have agreed with themselves -- that there is no military victory in Afghanistan," he said.

Obama hopes to start reducing troop numbers in July and to withdraw most US forces by the end of 2014.

In a boost for the plan, President Hamid Karzai said yesterday that Afghan forces would take over security this summer from NATO in areas including Helmand, a southern province where violence has dropped sharply.

Polls have shown that most Americans believe that the Afghan campaign is going badly, although the pessimism has waned slightly in the past year.