The four brothers who were said to be workers of a religious party, Ahle Sunnat Wal Jamaat were gunned down in their car at a roundabout in the New Karachi area.

Police said the brothers were sitting in the car late on Monday night when assailants on two motorcycles opened fire on them killing them instantly, while injuring one passerby.

"The four brothers were running a coaching centre in Gulshan-e-Iqbal and had no criminal records," a police official said.

He rebutted reports that the four belonged to the extremist Sipah-e-Sahaba organisation.

Besides the four brothers, three other people were also killed on Monday and the spate of killing continued today as target killers gunned down six more people.

In the city's Surjani Town area, two people associated with a political party, were killed when unknown assailants opened fire on them.

Similar firing incidents in New Karachi and Mominabad areas killed two others and injured one.

Tension gripped some parts of the city where the killings took place.

Karachi has been hit hard by such killings with over 1100 people killed this year in the city.

The menace of target killings which are either ethnic, religious or sectarian in nature has resurfaced after a brief lull.

Official figures state that since January this year when 55 people were gunned down, the number of people killed is around 1100 and 600 injured.