Pakistan's ruling coalition suffered a blow on Monday when the second-largest party in the alliance announced it was withdrawing its two ministers from the federal cabinet.
The Muttahida Qaumi Movement (MQM) said it was pulling the ministers out because of differences with the ruling Pakistan People's Party (PPP) of slain premier Benazir Bhutto.
The move comes just weeks after a prominent religious party walked out of the government, sparking fears the alliance could crumble.
People's Party (PPP) activists gather at the site where former prime minister Benazir Bhutto was assassinated.
An MQM statement said that government failed to curb corruption and control inflation and added that a decision to stay or leave the coalition at federal and provincial level would be taken in the near future.
"We have two ministers in the federal cabinet and as protest have withdrawn them, but we will not sit on opposition benches," Haider Abbas Rizvi, a senior MQM leader, said.
Federal minister for ports and shipping Babar Ghauri and federal minister for overseas Pakistanis Farooq Sattar would resign on Tuesday, he said.
Another party leader said the move was in response to a row over remarks made by the home minister of the southern province of Sindh, Zulfiqar Mirza.
"Our coordination committee has decided that our two ministers in the federal cabinet will resign tomorrow," Faisal Sabzwari said.
"The decision has been taken because the government did not pay any heed to our complaints about the remarks of Sindh home minister maligning the MQM," he told reporters.
Mirza prompted anger from the MQM by saying on television that most of the suspects detained in recent months over targeted killings had belonged to the MQM.
The party complained to Prime Minister Yousuf Raza Gilani and President Asif Ali Zardari about it, but were unhappy with their response.
Sabzwari said a decision would be taken later about quitting the Sindh provincial cabinet.
The MQM represents the Urdu-speaking majority in Karachi and shares power in Sindh province and central government. It has 25 seats in the 342-member national assembly.
Karachi, capital of Sindh, is plagued by ethnic and sectarian killings, crime and kidnappings.
Tensions are already high between the MQM and the Awami National Party (ANP), which represent different communities in Karachi, straddling political fault lines.
AFP /ls
