Taliban fighters have stepped up attacks against government interests as part of their 'spring offensive'

Taliban gunmen have attacked an Afghan road construction company in the eastern province of Paktia, reportedly killing at least 35 people and wounded another 20 in the worst single attack in months.

"A large group of Taliban attacked a road construction company in Paktia province. The fighting between the company guards and Taliban attackers continued for five hours," Rohullah Samoon, Paktia provincial spokesman, said on Thursday.

"Thirty-five guards and staff of the company were killed and 20 were injured. There were casualties on the Taliban side as well."

However, Taliban put the death toll at 40.

Zabihullah Mujahid, the Taliban spokesman, said the movement carried out the attack, killing 40 people and torching four vehicles.

He did not mention any Taliban casualties. The group is known frequently to exaggerate its claims.

The attack came a day after at least 13 people were killed and 20 others injured in a suicide bombing on a minibus carrying police cadets in eastern Afghanistan.

'Spring offensive'

It is thought to be the highest single death toll in a Taliban attack since fighters struck a bank in Jalalabad in February, killing many people including police collecting their salaries.

The Taliban have stepped up attacks against US-led troops in recent months especially after it announced its 'spring offensive' last month.

It has made Afghan government projects a prime target in a bid to undermine the authority of President Hamid Karzai's administration and have repeatedly kidnapped foreign road construction workers from camps in the past.

The Afghan militia have been waging a 10-year battle to evict foreign troops stationed in Afghanistan in the wake of the 2001 US-led invasion that toppled their government from power for sheltering Osama bin Laden.

There are currently around 130,000 US-led international troops in the troubled country although limited troop withdrawals are due to start from a handful of safer areas in July.

Paktia borders Pakistan's lawless border regions, where Taliban are known to have rear bases and is a highly volatile province frequently hit by violence and cross-border attacks.