Lahore - At least four people have been killed and 10 wounded in a blast which appeared to have been an attack targeting a census team in Pakistan's eastern city of Lahore on Wednesday, officials said.
Security officials had cordoned off the area on Bedian Road in the bustling capital of Punjab province after the blast, which rescuers said occurred just before 08:00am local time.
"It appears to have been an act of terrorism," Punjab provincial law minister Rana Sanaullah said in televised comments, adding that two soldiers and two civilians had been killed.
Rescue officials and police confirmed the toll, with a police official telling AFP the census team had been the target of the attack.
Teams of enumerators backed by the military and security forces are carrying out Pakistan's first census in almost two decades, an enormous and highly charged task that could redraw the country's political map one year before national parliamentary elections.
"Four people are dead so far and at least 18 injured, who were shifted to hospital," said rescue spokeswoman Deeba Shahnaz. The police official said at least 10 people had been wounded.
Lahore on edge
Shahnaz and other officials initially described the incident as a gas cylinder explosion, but said an investigation was ongoing.
There was no immediate comment from the military, and no group immediately claimed responsibility for the attack.
Lahore has been on edge since a wave of violent attacks across Pakistan in February killed 130 people and shook citizens emboldened by growing security.
The attacks included a bomb blast in the eastern city on February 13 which killed 14 people in an assault claimed by Jamaat-ul-Ahrar (JuA), a faction of the Pakistani Taliban.
Ten days later a fresh blast sent panic through the city when it killed eight people, though officials later said it was a gas leak, not an attack as initially feared.
Wednesday's explosion came days after at least 22 people were killed and 57 wounded on March 31, when a car bomb tore through a market in a mainly Shiite area of Pakistan's tribal belt in an attack that was also claimed by JuA.
February's assaults also included a suicide blast at a Sufi shrine in Sindh province which killed 90 people and was claimed by Islamic State.
The wave of violence has dented optimism after the country appeared to be making strong gains in its decade-and-a-half long war on militancy, with analysts speaking of a militant resurgence