At least 35 construction workers have been shot dead and 20 injured by Taliban insurgents in eastern Afghanistan, an official says.Eight insurgents were also killed as guards returned fire during Wednesday night's ambush, a Paktika provincial spokesman told the BBC.The attack took place in a mountainous district on the highway linking Paktia and Khost provinces.The Taliban recently declared the start of a "spring offensive" of attacks."A large group of Taliban attacked a road construction company in Paktia province," Paktia provincial spokesman Rohullah Samoon is quoted by the AFP news agency as saying."The fighting between the company guards and Taliban attackers continued for two hours."The men were attacked in a roadside camp next to the highway they were working on.Road workers are frequently targeted by Taliban militants. Last December gunmen kidnapped four Turkish road workers and their local driver in Paktika.Source: BBC