Three miscreants and an officer with the paramilitary troops, Rangers, were killed in exchange of fire between insurgents and security forces in the restive Lyari area of the city, Xinhua reported citing Dunya TV.
An official with Pakistan Navy was killed and his wife was injured when two unknown people riding motorbikes opened fire at their car near the city's National Stadium.
A man with a political party was killed in Shah Faisal Colony area. His body was later shifted to the Jinnah Hospital where doctors said he was shot in the head and chest.
Two bodies were recovered from Haji Camp area of the city. Police said the victims were kidnapped a few days ago and there were torture marks on the bodies.
A policeman was gunned down by unknown gunmen in north Nazimabad area of the city, bringing the death toll of policemen killed in the violence-hit city to 120 since the beginning of this year.
Four more people, including one with a religious group, were killed in separate incidents of firing by unknown gunmen Wednesday afternoon and night.
Police also recovered huge cache of arms and arrested over 20 insurgents from Baghdadi area of the city.
The history of violence in Karachi dates back to 1990s. However, the issue became intense over the last few years. Human right activists say that most of the killings take place due to political, religious and ethnic confrontation between various rival groups and mafias in the city.
According to Human Rights Commission of Pakistan, over 1,726 people including policemen, political activists and troops, have been killed during the first six months of 2013.
The wave of killings and kidnappings blamed on militants, criminals and political tensions led Prime Minister Nawaz Sharif to call a special cabinet meeting in Karachi Wednesday to restore peace in the city.