A roadside bomb targeting troops killed a civilian and left 16 more people including 11 soldiers wounded Thursday in Pakistan's violence-plagued port city of Karachi, police and military officials said.

Television footage showed several cars and motorcycles were damaged in the blast aimed at a truck carrying soldiers back to camp after they carried out security duties for by-elections in the city.

"At least 11 soldiers were wounded in the bomb blast on their truck," a military official told AFP.

"A civilian was killed and five others were also wounded," he added.

Police officials confirmed the bombing and toll.

Senior police official Irfan Bhutto said another bomb was found near the blast site attached to a pylon and a bomb disposal unit was attempting to defuse it.

An unprecedented wave of killings and kidnappings has hit Karachi, a sprawling metropolis of 18 million people on the Arabian Sea and Pakistan's economic heart.

Bloody gang wars fed by ethnic and political bitterness, drugs and the Taliban, have created a culture of impunity, and the past two years have seen record death tolls.

In the first six months of 2013, 1,726 people were killed in Karachi compared with a previous high of 1,215 in the same period last year, according to the Human Rights Commission of Pakistan.