The deafening explosion took place at about 8.15 a.m. in Karsaz area when the naval bus was carrying an estimated 35 people to office, Xinhua reported citing Duniya TV.
A Pakistan Navy spokesman said four navy officials aboard the bus were killed. A hospital official said a passer-by was also killed.
"The bus was taking navy officers to a dockyard when a planted bomb exploded nearby," a senior police official was quoted as saying by Geo News.
No militant outfit has taken responsibility for the incident.While one media report said the deceased include two lieutenants and a 19-year-old pedestrian, Geo TV cited hospital sources as saying that one of them was a woman doctor.
There were differing accounts on how the blast was carried out.Police sources said the bomb containing an estimated three kg of explosives was placed on a motorcycle and a remote control device was used to trigger the blast when the bus passed by the area.
Geo TV reported that the bomb was placed in a gutter near a petrol pump and went off when the bus crossed Karsaz Bridge on Shahrah-e-Faisal.
Eyewitnesses said the blast threw the bus four to five feet into the air.Senior police official Iftikhar Tarar said the blast appeared to be the work of the same group behind Tuesday's twin bombings that killed four navy officials and wounded nearly 60 people.|
On Tuesday morning, two naval buses carrying officials to work were blown up in two different locations in the city, leaving four people, including a military lady doctor dead and 56 injured.
In another incident in the port city, bomb disposal squad personnel defused a bomb weighing about 10 kg placed at the Northern Bypass, thus saving many lives.
Deccan Herald is on WhatsApp Channels| Join now for Breaking News & Editor's Picks