Lahore, Feb 23 (IANS): At least eight persons were killed on Thursday when a powerful explosion took place near a restaurant serving Indian cuisine in the Pakistani city Lahore, police said.

Punjab Law Minister Rana Sanaullah said 21 people were injured and were shifted to the General Hospital where four were in critical condition, Xinhua news agency reported.

Police spokesman Nayab Haider said the blast was triggered by detonation of explosive materials in Defence area.

The bomb disposal squad said a timer device was used to carry out the explosion and that eight to 10 kg of explosives were used in the attack.

The blast occurred in an under-construction building, located right next to Bombay Chowpatty, a restaurant that serves Indian cuisine.

At least four vehicles and 12 motorbikes were destroyed in the explosion. Four nearby building were also damaged.

Heavy contingents of police, army and people from intelligence agencies reached at the blast site and cordoned it off, Xinhua reported.

The army vacated all the nearby buildings in the market and launched a rescue and search operation.

A few days ago, the same market was evacuated and checked by law enforcement agencies after receiving a bomb threat by some outlawed group.

No group has claimed responsibility for Thursday's attack.

Officials, however, denied that a second blast took place in Lahore, the capital of Punjab province.