At least four people were killed and over a dozen others injured when an explosive-laden vehicle exploded inside the parking lot of Serena hotel in Quetta, capital city of Pakistan's southwest Balochistan province, Wednesday night, the country's Interior Minister Sheikh Rasheed Ahmad said. He said that despite the security measures, the vehicle carrying explosives managed to enter the parking lot from the main gate of the hotel, which is a matter of big concern and the responsible people will be taken to task for creating a security lapse which gave terrorists a chance to carry out the attack.