Karachi:Some 42 people have been killed and scores injured in ethnic and sectarian violence in Pakistan's financial capital in the last three days, amid growing tensions between the ruling PPP and its estranged ally Mutthaida Qaumi Movement (MQM).

The violence is blamed on political and ethnic differences between the Pashtun-dominated Awami National Party (ANP) and the Urdu speaking MQM, which has considerable influence in Pakistan's largest city.

According to police and rescue officials, the number of victims was 28 on Wednesday, with around 30 people injured.

The toll on Thursday touched 42, with scores having been injured in the wave of violence since the last three days.

A six-year-old girl and a fruit vendor were killed in the worst-hit Qasba Colony area of Orangti Town due to firing.

The worst incident occurred early on Wednesday when five people were hijacked and killed in a public transport bus in Gulshan-e-Iqbal area.

There were reports of people migrating from their homes in Qasba Colony area where tensions between the MQM and the Pashtun-dominated ANP have been high.

"We have no option but to move to safer location in these conditions there is no one to listen to us," Saeed Ahmad a member of an effected family said.

The residents accused the police and Para-military Rangers of inaction despite miscreants resorting to indiscriminate firing from the hills surrounding the colony which is dominated by the Pashtun speaking people.

Television channels showed footage of houses in the colony riddled with bullet holes and people fleeing their homes for safety.

The MQM recently quit the PPP-led coalitions at the Centre and the southern Sindh province amid political differences. ANP is still a partner of the coalition.

Tensions between the two parties have been blamed for the surge in ethnic and sectarian killings in the city. There is a looming threat that the MQM, which has widespread influence in Karachi, would call a general strike to protest the killings of its party workers.

Political analysts have expressed fears that it could cripple the country's economy as Karachi is the financial hub of Pakistan. The key port city is also the main hub used by NATO forces to transport goods to Afghanistan.

"Karachi has lot of resilience because it has seen sectarian, ethnic and political related violence and killings in the past but this time strikes could really hit the economy bad (hard) as the country is already struggling economically," Professor Zamir Ahmed said.

MQM supremo Altaf Hussain earlier warned from London, where he lives in self-exile, that he would be forced to call a strike to dislodge the Government if his party workers continue to be targeted.

Police said they had detained several suspects in connection with the ongoing violence.

The Human Rights Commission of Pakistan says 490 people have already been killed in targeted killings this year. Some 748 in 2010 and 272 in 2009 were killed in sectarian and political violence.