|The MQM, whose main support base is located in the city of Karachi, will now sit on the opposition benches [File: EPA]
Pakistan's president has said he supports Yousuf Raza Gilani, the prime minister, against any attempts to destabilise the federal government after a crucial partner quit the ruling coalition.
Asif Ali Zardari, the president, and Gilani are from the same political party, PPP, and both would be loath to face an early general election.
"[Zardari] has full confidence in ... Gilani and solidly stands behind him in foiling any attempt to destabilise the coalition government," Farhatullah Babar, the presidential spokesman, said in a statement on Monday.
Gilani's government lost its parliamentary majority when the Muttahida Qaumi Movement (MQM) announced on Sunday it would go into opposition over government fuel-price policies that it said were "unbearable" for Pakistanis.
Gilani has been trying to win the support of opposition leaders to try and save the governing coalition, led by the PPP.
The political crisis comes as the Pakistani government struggles to meet demands placed on it by the International Monetary Fund, including politically sensitive tax overhaul, in return for the remaining tranches of a $11bn loan.
The country's main stock index ended 1.44 per cent lower on Monday, reflecting concerns over the stability of the government, traders said.
Speaking to Al Jazeera on the MQM's parting of ways with the PPP, Mosharraf Zaidi, an independent political analyst, said: "It's not a divorce under irreconcilable differences. It is more like a squabble that can be resolved."
He said Gilani's government "will have to demonstrate that it has the necessary numbers in parliament to validate it being in power".
Without the MQM's 25 seats, the PPP's coalition strength - 160 seats in the 342-member National Assembly - is 12 short of the 172 required for a majority.
The opposition, which includes the PML-N of former prime minister Nawaz Sharif, has not yet sought a no-confidence vote against Gilani in parliament.
No decision taken
Faisal Subzwari, an MQM politician, told the Reuters news agency that the party had not taken any decision on a vote on the government. The MQM said its senators had submitted a motion seeking a rollback of fuel price rises.
Since January 1, petrol prices have risen by nine per cent, adding to inflationary pressure.
The MQM has also been complaining for months that the government was not doing enough to improve security in its home base of Karachi, Pakistan's financial capital and biggest city.
The party's pullout was the second blow to the government after the Jamiat-e-Ulema-e-Islam (JUI), a religious party, quit last month and went into opposition after Gilani dismissed one of its ministers.
Al Jazeera's Kamal Hyder, reporting from Islamabad, said: "There are some tough times ahead, and if the opposition gears up, the government will not be able to move any legislation" in a divided National Assembly.
"The government is now beleaguered because it has become unpopular, [there is] misgovernance, and mishandling of the economy."
Speaking to Al Jazeera on Sunday, Haider Abbas Rizvi, MQM's deputy parliamentary leader, cited government corruption, rising prices and a regressive tax policy as the factors behind the party's withdrawal decision.
"The poor and middle class people are being taxed by the government, but the rich and the feudals are not being taxed," he said.
Rizvi asserted that the MQM was not seeking to destabilise or overthrow the Gilani government.
"Our idea is certainly not to support the government, but we do not want to become a part of derailing the existing political system in Pakistan. We would ... support, while sitting in the opposition, all the good ideas of the government in parliament," he said.
"We have no intention whatsoever to derail the government."