At least 12 persons were killed and over 30 others injured on Tuesday in a passenger bus and truck collision in Pakistan's Sindh province.The accident took place when the speeding bus travelling towards Karachi from Dera Ismail Khan rammed onto the stationary truck, Dawn online reported.The bus was carrying around 50 passengers and authorities said the toll is likely to increase.The victims included women and children, while some of the injured were reported to be in critical condition.