Islamabad, Jan 23 : Millions of Pakistanis encountered a power outage on Monday after the electricity distribution system of the country broke down, said the Ministry of Energy. The Ministry said in a statement the countrywide power breakdown was triggered after the frequency of the national grid decreased suddenly, reports Xinhua news agency. "According to initial reports, the system frequency of the national grid system decreased at 7.34 a.m. in the morning, which resulted in a widespread breakdown in the power system," it said. The Ministry added that efforts were underway on a fast track to restore the system as early as possible. Local media quoting unanimous officials from the Ministry reported that it might take 24 hours to restore the system completely. According to the local reports, all major cities including the capital Islamabad, Lahore, Karachi, Peshawar and Quetta have lost power supply completely. Quetta Electric Supply Company told local media that 22 districts of the Balochistan province are without power. /IANS