A resurgence of the Taliban and criminal warlords in the northern provinces of Afghanistan is threatening to stretch a U.S.-led coalition thin just as NATO pushes to stabilize southern Afghanistan, officials said.

Taliban insurgents gained control last week of Dahne Ghore district, in northern Baghlan province, for two days. Six Afghan police officers were beheaded in a government building in the district.

"The Taliban controlled the area for two days before NATO could do anything," an Afghan official told The Washington Examiner, on condition that he not be named. "NATO and the [Afghan] government were ashamed of what had happened and wanted to keep it quiet."

Insurgents, which include Pashtuns, Tajik, Uzbek, and other foreign fighters from Central Asia are also actively trying to establish strongholds in the northern areas of Takhar, Kundoz, Jawzjan, Sar-e-pul, Samangan, Faryab, Badghis and Balkh, Afghan officials said.

To combat the northern surge, coalition forces this year have been forced to keep nearly 10,000 troops in the north this year. That is up 40 percent over 2009, NATO spokesman Polish army Maj. Marcin Walczak said.

"To counter the rise in attacks, combined forces continue to push into Taliban safe havens like Bagh-i-Shirkat on the outskirts of the provincial capital Kunduz city," Walczak said. "Warlords, criminal groups, drug smugglers and tribal feuds continue to have negative effects, and an increased insurgent emphasis has resulted in rising attacks since 2009."

As part of the Obama administration's troop increase in Afghanistan, battalions from the 10th Mountain Division will soon be deployed to the northern part of the country, to partner and train Afghan National Security Forces in an effort to hold off the insurgency. The division will work closely with "national police in key districts," NATO officials said.

Afghan and coalition forces have reduced insurgent activity by the establishment of new outposts in the region, Walczak said. In June, a combined forces operation lead to the detainment of Baghlan's chief of finance, who was an expert bomb maker and commander of three insurgent cells in the area. In May, Afghan and coalition troops "removed three successively appointed Taliban provincial shadow governors for Baghlan province," Walczak added.

As soon as the Taliban are removed, replacements show up, said another Afghan official, who is familiar with areas in the north and the increase of insurgent fighters. "The Taliban is trying to stretch the coalition forces thin until the drawdown date of next year," he said.

"The insurgency is attempting to exhaust the U.S. and NATO and they have the patience to wait it out," the Afghan official said. "Unfortunately, NATO does not."