KABUL — Taliban insurgents dealt a serious blow to one of the Afghan Army’s most highly regarded units Friday, killing 13 soldiers and overrunning their remote outpost in eastern Afghanistan.
According to Afghan security officials, speaking on the condition of anonymity because of the delicate nature of the Taliban victory, the 13 soldiers constituted the entire complement at the checkpost. One police official said that a force of 200 Taliban fighters had opened fire with heavy weapons and finally set the post on fire; most of the deaths were from the flames.
It was one of a series of bloody insurgent attacks in the current spring offensive that have helped drive the rate of government fatalities to the highest level of the war. Afghan soldiers and policemen are dying at more than double the rate of a year ago, according to military officials.
The numbers underscore how much more of the fighting has been handed to Afghan forces and raise questions about how ready those forces are for the increased responsibility, even as the insurgents ratchet up their much-anticipated spring onslaught.
This year has seen a number of high-profile insurgent attacks on the ground, not just the remote-control and suicide bombings the Taliban favored in the past. The shift suggests that they are testing how well Afghan forces operate on their own at a critical juncture in the planned withdrawal of the US military.
The NATO transfer to Afghan control is scheduled to finish in the next few months, with Afghan forces taking over security in 100 percent of the country, and NATO and US military forces moving to a support and training role as their numbers diminish.
“We know the enemy’s going to come out hard this summer, so the numbers are going to go up,’’ said Colonel Thomas Collins, a spokesman for the International Security Assistance Force.
Friday’s attack was on the Third Battalion of the Second Brigade, one of only a handful of Afghan army battalions rated by the US military as independent and able to operate on its own without foreign advisers. It was one of two such battalions that had been deployed without advisers recently in Kunar Province, according to a military official, who spoke on the condition of anonymity because he was not authorized to discuss the subject.
The Third Battalion was assigned to hold the Narai district, a rugged, mountainous area near the Pakistani border, on a route used by insurgents.
A spokesman for the Taliban, Zabiullah Mujahid, took credit for the attack and claimed that 15 soldiers had been killed and that the insurgents had captured all of their weapons and ammunition.
It was a measure of the delicacy of the episode that officials publicly played down the death count, with a spokesman for the 201st Corps confirming only that an attack had taken place, and the Kunar Province police chief, General Habib Saidkhelli, saying that only two soldiers were killed.
The Narai district police chief, Mohammad Yousuf, confirmed that 13 soldiers had been killed.
The Third Battalion has been widely praised as among the best of the Afghan army’s formations.
The soldiers at the checkpost were taken by surprise because the Afghan and US militaries were concentrating on a joint operation elsewhere in Kunar, said a military official in the area.
The Second Brigade commander, Colonel Hayatullah Aqtash, flew up in his personal helicopter with supplies Friday morning to begin rebuilding the outpost, the official said.
Aqtash, reached by phone, was dismissive of the attack. ‘‘It is a routine incident,’’ he said. ‘‘Every day we face such attacks.’’
While it is still early in the spring fighting season to generalize, the insurgents have initiated several attacks recently using foot soldiers or made what the military calls ‘‘complex attacks,’’ involving bombings as well as firefights. Last year, the insurgents relied largely on suicide bombers and roadside bombings and avoided engaging directly with Afghan or international forces.
In March, ground attacks by the insurgents killed four police officers and four Afghan soldiers in the Dangaam district of Kunar province. Officials there said Friday’s attack was the deadliest in at least six months.
In northern Badakhshan province, an area with little previous insurgent activity, Taliban forces ambushed a convoy and killed 17 Afghan soldiers sent.