Militants on Wednesday dumped the mutilated body of a purported Afghan spy accused of collaborating on US drone strikes that killed a prominent warlord in Pakistan this month, officials said.

The body of the man identified as Asmatullah Kharoti was found in Wana, the main town of the South Waziristan tribal district, which borders Afghanistan.

Local officials said he had been shot dead and there were wounds on his neck.

Two notes on the body ordered the remains to be left on the roadside until 10:00 am (0500 GMT) "so that everyone could see the fate of spies", and the second accusing him of being a spy and being responsible for US drone attacks.

"He is a spy and was giving information to US and ISAF forces in Afghanistan about our activities," a local official quoted the note as saying.

"He is responsible for the killing of five of our senior members, including Mullah Nazir, in drone attacks. He confessed that he installed chips in digital Korans."

Nazir was killed in a US drone strike on January 2. He was the main militant commander in South Waziristan and sent insurgents to fight US, NATO and Afghan government troops in Afghanistan, and was accused of sheltering Al-Qaeda.

He was one of the most high-profile victims of US drone strikes in Pakistan, which Islamabad publicly criticises as a violation of sovereignty but which US officials believe are a vital weapon in the war against Islamist militants.

Two militants from Nazir's group who spoke to AFP accused Kharoti of giving Nazir a digital Koran, fitted with chips to track his movements, during a meeting at an undisclosed location in Afghanistan.

"He presented Nazir and others digital Korans as a gift which were fitted with chips which help US drones strike their targets," one of the militants said.

"When Mullah Nazir was returning, US drones fired missiles at him in Pakistani area," he said.

Lacking air power, Afghans to rely on mortars: US
Washington (AFP) Jan 23, 2013 - Afghan forces will have to rely increasingly on mortars and armored vehicles instead of air power once NATO-led forces withdraw from the country in 2014, a senior US general said Wednesday.

US air strikes in the war already have begun to decline and the general's comments underlined the shift underway in Afghanistan, as US and coalition combat forces gradually depart over the next two years.

With a fledgling fleet of helicopters, the Afghans will not have the option of calling in bombing raids like their NATO counterparts, who routinely ask for back-up from warplanes and attack helicopters.

As a result, US troops are focused on building up the Afghan army's arsenal of mortars and howitzers, said General James Terry, the deputy commander of US troops and head of the International Security Assistance Force joint command.

Given the Afghans' lack of air power, "what we must do then is bring the surface fire capability to fruition, and that's the indirect fire -- observed indirect fire," Terry told reporters at a Pentagon briefing.

The Afghans would be employing D-30 howitzers and 60 mm mortars, he said.

"And so now, instead of, you know, calling up into the air, they have those organic capabilities inside their formations," he said.

He also said seven Afghan battalions would use armored vehicles that would give the Kabul government forces a degree of mobility until their nascent air force expands.

The "armored wheeled-based platform" for Afghan forces currently is not armed but a gun system possibly could be added, he said.

The Afghans will have to evacuate most of their wounded soldiers with vehicles instead of air, as a large fleet of NATO helicopters manned with medical teams will no longer be at the ready, he added.

"In terms of the casualty evacuation, we're starting to move toward ground casualty evacuation," Terry said.

US bombing raids in Afghanistan have begun to decrease, according to Pentagon statistics, apparently reflecting the drawdown of NATO forces and a gradual handover to Afghan army and police.

The number of incidents in which US aircraft launched weapons in Afghanistan in 2012 dropped to 4,092, down by about 24 percent compared to the previous year, according to the latest figures from the US Air Force.

In 2011, there were 5,411 "weapon releases" by US warplanes.

But the number of strikes by unmanned drone aircraft has increased, from 257 in 2009 to 506 in 2012, it said.

There are currently about 66,000 US troops in Afghanistan and the bulk of the force is due to pull out by the end of 2014.

US officials say President Barack Obama's administration is weighing plans to retain a small force of several thousand troops after 2014.