At least four people have been killed in a blast which appeared to have been an attack targeting a census team in Pakistan's eastern city of Lahore Wednesday, officials said.

"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 saying the census team had been the target of the attack.