Karachi, Pakistan's commercial capital and home to its main port, has a long history of political, ethnic and religious violence and the clashes have raised fears of a return to the bloodshed that plagued the city in the 1990s.
The violence, which broke out on Saturday, is between the city's majority community of Urdu-speakers, most descendents of migrants from India at the time of the partition of India in 1947, and ethnic Pashtuns from northwest Pakistan.
Rivals fought gun battles and burned shops and cars in several parts of the city of 15 million people on the weekend. More disturbances erupted on Monday and hospital officials reported another five deaths.
Provincial interior minister Zulfiqar Mirza told the provincial assembly police and paramilitary rangers had been deployed in all sensitive areas.
"Police and rangers are patrolling the areas but the political parties should also play their role to calm the situation," Mirza said.
Police have been told to shoot trouble-makers on sight and they have banned pillion riding on motor bikes.
Mirza said 20 people had been killed but according to a tally of reports from police and hospitals, the death toll was at least 30.
All schools and colleges in the city were shut on Monday and public transport was thin. But operations at the country's main port was normal, a port official said, while financial markets and banks were open.
‘Buy Guns’
Tension has been rising since leaders of the Urdu-speaking community began saying Taliban militants, most of whom are ethnic Pashtun, were gaining strength in the city.
A political party representing Urdu-speakers, who are known as mohajirs, or refugees, has been the dominant political force in the city since the 1980s.
A large number of Pashtuns and members of other Pakistani ethnic groups have flocked to Karachi over the years in search of work. Pashtuns dominate the city's transport network.
Taj Haider, a senior member of the ruling Pakistan People's Party, said trouble had been brewing for some time.
"It is not sudden. It was going on for a while. They were asking people to buy guns because Taliban were coming," said Haider, referring to the Muttahida Qaumi Movement, or MQM party which is mostly supported by Urdu-speakers.
Faisal Sabzwari, an MQM member of the provincial assembly, said the violence stemmed from frustration over rising crime.
"For a few months criminal activity against innocent people has increased. Incidently, most of the criminals belonged to a particular ethnicity," Sabzwari said.
"Taliban people are involved," he added.
Pashtun politicians say the MQM uses fear of the spread of the Taliban as an excuse to treat Pashtuns unfairly.
