Hundreds of people have been killed in ethnic and political gang war in the last few months in Pakistan's largest city Karachi, leading to calls for the army to stop the violence.

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Pakistan's key city port Karachi is one of the largest cities in the world and in recent months has become one of the deadliest.

Around a thousand people have been killed in the last year, with 300 of them killed in July alone.

The violence is blamed on gangs with links to three rival political parties - the ruling Pakistan People's Party, the Muttahida Qaumi Movement (MQM), which dominates Karachi, and the ethnic-Pashtun Awami National Party.

Thugs and ethnic gangs appear to have been used by political parties as foot soldiers in a turf war in the city, but all three parties deny any involvement

The violence has become so bad, that many people have called for the military to step in, especially to protect the commercial hub. And now there are signs that they may just do that.

Karachi has always been a volatile city with a turbulent past but even by its standards the recent violence has been shocking. Channel 4 News presenter Saima Mohsin looks at the issues:

"Aside from gang warfare and violent rioting target killings have seen a steady increase with some high profile deaths. Each murder sees a retaliatory attack or similar killing.

"Reporters who have covered the city's streets for more than three decades say this is as bad as it gets. But this is not down to terrorism as you might expect. Karachi is the arena of bloody turf wars sponsored by political groups not content with political power alone - it's bricks as well as ballots that count here.

"Ethnic violence is also enshrined in the political violence as warring factions come from different backgrounds. The parties are divided by geography and ethnicity rather than political manifestos."

Read more from Saima Mohsin: Pakistan's bloodiest city

General Ashfaq Kayani told The News newspaper that Pakistan's military is ready to help stem the tide of violence sweeping Karachi, if the civilian government asked it to do so.

The News said Kayani expressed "grave concern" over the security situation but also said he was sure the police and paramilitary forces could contain the violence if properly deployed.

"Karachi is the jugular vein of country's economy and it will be great injustice if the deteriorating law and order situation is allowed to continue for a longer period," the newspaper quoted him as saying.

However experts say that the army, already tied up fighting Taliban and Islamist militants, is not well placed to play the role of peacemaker.

Karachi has a long history of violence, and ethnic, religious and sectarian disputes and political rows can often explode into battles engulfing entire neighbourhoods.

The city contributes to much of Pakistan's wealth and is a vital commercial hub with the stock exchange and central bank based there. Worried business leaders called on the army to intervene to stop the violence.

In the 1990s, the army carried out an operation in Karachi, primarily against the MQM, which was blamed for instigating violence at that time.

"There is law in Karachi but there is no order," said Khalid Tawab, vice president of the Federation of Pakistan Chambers of Commerce and Industry. "Everything is going from bad to worse."

The police has failed to restore peace, and now we need the army to come in and do that, and bring to an end the sufferings of the people of Karachi."

Leaders of the Karachi Chamber of Commerce and Industry, as well as almost all the main business and trade associations, have made similar demands. But politics may prevent the intervention of the military.

"The army will not work on a political agenda," said Mutahir Ahmed, professor of international relations at the University of Karachi.

"In addition to the army itself, the government will also not want to involve the military in Karachi, as it will be a serious blow to its credibility. Politically, the PPP will suffer the biggest damage from such a move."