KOLKATA: A key partner in India’s ruling coalition withdrew support from the government on Tuesday and said its ministers would resign in protest over a series of economic reforms.

“Our ministers will go to Delhi to resign. We will not stay in UPA II,” the head of the regional Trinamool Congress party, Mamata Banerjee, told reporters, referring to the ruling coalition led by the Indian National Congress party.

The withdrawal of Trinamool, which is staunchly opposed to allowing foreign supermarkets into the retail sector, leaves the government weakened and dependent on outside support to pass legislation.

The reforms unveiled by Prime Minister Manmohan Singh last week include allowing in foreign retail giants such as Walmart and Tesco, as well as foreign airlines, and hiking the price of subsidised diesel by 12 percent.

Banerjee, a mercurial politician who has forced the government into a series of policy U-turns, swept to power in the state of West Bengal in May last year.

“My party’s six ministers have decided to resign. It is time to fight the battle alone,” she said after a meeting of Trinamool leaders in Kolkata, the capital of West Bengal.

The populist firebrand, who said the reforms would hurt the poor, said: “Unfortunately we have not received any respect from Congress despite being their important coalition partner.”

Trade unions, backed by the main opposition Bharatiya Janata Party (BJP) and other regional parties, have called for a nationwide strike on Thursday against the reforms, which have been welcomed by business leaders and investors.

The country’s biggest union of truckers announced Tuesday it would also join the day of defiance, increasing pressure on Singh and his reformist new Finance Minister P. Chidambaram who said reforms were necessary to repair India’s strained finances and attract foreign capital and investment.

“I am saddened by the prospect. We knew that she could take any decision.

As expected, she has taken one,” Congress leader Sandeep Dikshit told NDTV after Banerjee’s announcement.

There has been speculation for months about the possibility of early elections before their scheduled date in 2014 because of tensions in the UPA coalition.

Congress insiders believe they will be able to manage by calling on other regional parties such as the Samajwadi Party or the Bahujan Samaj Party from northern Uttar Pradesh state.

“She (Banerjee) has made the situation very difficult,” said R.B. Guha, a political science professor in Kolkata. “The Congress will now have to appease so many other regional parties to stay in power.”