Over 50 people were killed in a traffic accident along a highway in Afghanistan's Samangan province on Thursday, police said."A long-distance bus collided with an oil truck on a bridge around evening. The bus plunged into a 20-meter-deep ravine after the crash, leaving over 50 people dead and dozen others injured," a police source told Xinhua news agency.The bus was travelling from Mazar-i-Sharif city, capital of northern Balkh province, to Kabul, the national capital.Earlier, Munir Rahimi, a provincial police officer, said "the initial reports showed 24 were killed and 21 others were wounded in the accident".Afghan officials blame reckless driving as the main cause of road accidents in the country.