At least 19 people were killed and over 40 others injured in a head-on collision between two passenger buses in Pakistan's Punjab province on Sunday night, police and media said.According to reports, the accident happened on Multan road in Dera Ghazi Khan district, reports Xinhua news agency.One of the passenger buses was completely destroyed in the accident, reported TV channel ARY News, adding that the bodies of the dead and injured were retrieved after cutting parts of the buses.A hospital official said the death toll might further rise as several injured were in critical condition.Police officials in the area said the accident happened due to speeding and negligence of one of the bus drivers.According to official data, around 9,000 road accidents are reported every year in Pakistan, claiming more than 4,500 lives on average annually.