Karachi, June 19 (AP): Youths rampaged through Pakistan's biggest city overnight, torching a police booth and erecting blazing barricades to protest 10-hour power cuts - a fresh headache for the government of President Gen. Pervez Musharraf.

Electricity shortages have struck much of Pakistan just as temperatures top 40 degrees Celsius, forcing businesses to close or throw away perishable products and leaving residents stewing in their homes.

Resentment at the outages has begun boiling over into the streets of Karachi, the country's main port and business capital, where anger is focused on the privatized local power utility.

In four neighborhoods suffering a sustained power outage late Monday, enraged youths piled old tires, empty fruit boxes and chairs stolen from nearby shops in the streets and set them ablaze.

A mob also burned a police kiosk in the city's Teen Hatti area, destroying computers and radio equipment along with records of traffic violations, said Falak Khursheed, traffic police chief.

Roads were jammed for hours as police diverted vehicles away from the unrest until authorities managed to restore power to the affected districts.

There were no reports of arrests or injuries.

The rapid growth of Pakistan's 160 million population and fast economic growth have produced skyrocketing demand for electricity. Musharraf plans to build several huge new hydroelectric dams, but those projects won't be realized for years and authorities are struggling to meet current needs.