Over 14 people were injured on Saturday when angry members of the Pakistan People's party clashed with the police, blocked roads and forced closure of shops to protest against Thursday night's attack on the convoy of former prime minister Benazir Bhutto [Images] that killed 165 people.

Groups of PPP supporters, some of them waving the party's flag, pelted stones, burnt tyres and caused traffic snarls at Safoora Goth, University Road, Sachal Goth, Lyari, Mauripur Road and Gadap areas.

In Lyari town, a PPP stronghold, Bhutto supporters exchanged fire with the police while a group of protesters torched a private car in Patelpara, tried to set fire to a petrol pump and stoned a KFC outlet in the southern part of the city.

Superintendent of Police in Lyari Fayyaz Khan said that the trouble started when some supporters of the PPP tried to force some shopkeepers to down shutters during the three-day mourning period announced by the party. "The police confronted these miscreants who than fired upon them and the ensuing exchange of fire left 14 people injured," Khan said.

He added that there had been other scattered incidents of people burning tyres and forcing closure of shops in some parts of Karachi.

Most streets and roads of this usually bustling city wore a deserted look on Saturday, a sharp contrast from the jubilation witnessed on Thursday when tens of thousands of  PPP workers had turned out to welcome Bhutto on her homecoming after eight years in self-exile.

Local authorities stepped up security by deploying additional police and paramilitary forces, especially on roads leading to Bilawal House, Bhutto's home in the city.

Residents of Pakistan's largest city were hit hard by the closure of most of the 300 petrol pumps, which resulted in public transport going off the roads. Some petrol pumps were closed as a precautionary measure by their owners after protestors tried to burn one of them.

Protests by PPP workers were also reported from other cities inlcuding Larkana, Thatta, Hyderabad and Saeedabad in Sindh province, which have traditionally been PPP strongholds. Courts were also boycotted in parts of the Sing province.

Bhutto, who called for three days of mourning for victims of the suicide bombing on Friday, has put off plans to visit Larkana to pray at the tomb of her father Zulfiqar Ali Bhutto. "We are observing a three-day mourning over the tragedy. The mourning will end on Sunday and then she will decide about her plans," said PPP spokesperson Sherry Rehman.

Rehman said Bhutto was at her Bilawal house, adding, "We are concerned about her safety but she is interested in going out to meet the people."

Dozens of people injured in the attack are still being treated in Karachi's hospitals, where many people gathered on Saturday to donate blood.