A paramilitary soldier frisks a motorcyclist on a street in Karachi on October 20, 2010, following an attack by gunmen in a market. — Photo by AFP

KARACHI: Paramilitary troops went house to house rounding up dozens of men in Karachi’s Orangi Town neighbourhood Tuesday as part of a crackdown on soaring violence in the city.

The operation came after a week of targeted killings that left more than 40 people dead in Karachi, a city of 18 million people with a long history of ethnic, religious and other violence.

But it was unclear how serious the crackdown by the Army Rangers really was, or whether it would have any long-term impact.

Orangi Town was the focus Tuesday because it was the worst hit during the recent spate of violence. Some 15 people, including several political activists, in the neighbourhood fell prey to unknown gunmen in the past week.

Around 1,500 paramilitary troops cordoned off part of the neighbourhood and conducted house to house searches, said Army Rangers' spokesman, Maj. Farooq Bilal. Media were not allowed into the neighbourhood.

''This operation will go on until the objectives are achieved — there is no time limit,'' Bilal said.

''We have detained some people who will go through a screening process.''

Karachi, a port city that is the country's main financial hub, occasionally endures such spates of violence.