Two bicycle bombs exploded minutes apart in Pakistan's eastern city of Lahore, killing at least six people and injuring more than 30, police and security officials said.

The first bomb went off near the historic Minar-e-Pakistan monument in a crowded area of the city, killing one person and wounding 13, local police officer Amir Zulfiqar told AFP on Thursday.

The device killed the owner of a nearby handcart, Zulfiqar said, adding that the condition of the injured people was not serious.

Minutes later a second blast in Icchra, Lahore's busiest shopping district, killed another five people, Lahore police chief Tariq Saleem Dogar told AFP.

"A bomb exploded near a cigarette kiosk and it triggered an explosion in a nearby fireworks shop," added Icchra police chief Waqar Ahmed.

"Four people were burned to death instantly and up to 20 people were injured," he said. Another injured person died on his way to hospital, police said.

A senior security official, speaking on condition of anonymity, said both bombs were attached to bicycles.

"A stranger came and parked his bicycle under an electric transformer and a few minutes later there was a big explosion," shopkeeper Mian Imtiaz told AFP at the scene.

"The place was filled with black smoke and I saw many people lying in a pool of blood and crying for help," he added. "It was very crowded when the explosion happened."

Police and ambulances rushed to the site and carried the injured to hospital. The blasts broke windows of several shops and the smoke blackened nearby hoardings.

Separately, two people were injured when two bombs exploded in the town of Kalat in the restive southwestern province of Baluchistan, police said.

The first bomb went off near a gas pipeline on Wednesday evening, said local police officer Ghulam Sarwar. He said the blast caused no casualties or damage to the pipeline.

About 15 minutes later another bomb shattered windows of a telephone exchange and injured two passers-by, he said, adding that the bombs were low-intensity devices.

Police also found a packet containing about one kilo (2.2 pounds) of explosive near a drain in the provincial capital Quetta.

No one claimed responsibility for any of the blasts.

PHOTO CAPTION

Pakistani policemen in Lahore. (AFP)