The death toll from violence across Pakistan's largest city, Karachi, has risen to at least 93 as authorities try to quell the political and ethnic turmoil.

Police officials said Saturday they have detained more than 150 people on suspicion of roles in the violence in several of the city's neighborhoods. The chaos has left scores wounded.

Authorities have ordered Pakistani security forces to shoot on sight when confronting disorders in Karachi.

About 1,000 additional police and paramilitary forces were deployed in Karachi Friday, joining forces already there, with new orders to shoot any armed “miscreants” they encounter.

There has been a series of targeted killings since Monday. At least 34 people died on Thursday alone when gunmen opened fire on buses.

Police say the killings are part of clashes between political groups in Sindh province, including the Muttahida Qaumi Movement and its rival, the Awami National Party .

The MQM largely represents the Urdu-speaking community, and until last month was part of the ruling coalition in Sindh. ANP represents ethnic Pashtuns. Both those groups and the ruling Pakistan People's Party are believed to have links to armed groups in Karachi.

MQM leader Raza Haroon has said his movement's supporters are being targeted because the party quit the coalition.

The Human Rights Commission of Pakistan says 490 people were victims of targeted killings in Karachi in the first half of this year.

Amnesty International has criticized the government's order for security forces to “shoot on sight” armed men involved in the violence. The rights group said Friday that by giving troops such power the government is effectively declaring Karachi “a war zone” and encouraging further lawlessness and violence, citing what it said was the army's record of human rights violations.

About 18 million people live in Karachi, the country's economic hub. The city also has been the scene of sectarian violence between Sunni and Shi'ite Muslims and militant attacks.