New Delhi: The ruling United Progressive Alliance continued on shaky grounds on Sunday as ally DMK remained adamant on walking out of the Manmohan Singh government over seat-sharing for the Tamil Nadu polls while the Congress adopted a wait and watch attitude.

The DMK said its six ministers would submit their resignation on Monday to the prime minister. The alliance came apart after the Congress asked for 63 of the 234 seats for the April 13 assembly polls, while the state's ruling DMK was willing to concede only 60.

"The ministers will be submitting their resignation letters tomorrow (Monday)," DMK leader T.R. Baalu told reporters in Chennai.

If the DMK ministers - two cabinet and four ministers of state - formally withdraw, the Congress-led UPA government will be reduced to minority in the 543-member Lok Sabha, though it has outside support of some parties.

The DMK's 18 MPs gave the UPA a slender majority of 274 in the Lok Sabha - the majority mark being 272. Without the DMK, the UPA would be reduced to 256.

But the DMK has said it will give 'issue-based support' to the UPA government.

The Congress has outside support of Samajwadi Party (22 MPs), Bahujan Samaj Party (21) and the Rashtriya Janata Dal (4). All these parties also give issue based support to the UPA.

The DMK's withdrawal is likely to complicate matters for the UPA as the government's priority is to get the 2011-12 union budget passed in parliament during the current session. If the government fails to pass the budget vote, it will fall.

Jolted by the DMK's pull out decision, the Congress on Sunday appeared on a "wait and watch" mode and weighing its options. According to a source in the party, the Congress was waiting for the DMK to reconsider its withdrawal decision before restarting seat-sharing talks.

But Baalu in Chennai said that no one from Congress had contacted the DMK after it announced its decision. Congress leaders refused to speak on record about the issue.

"I have nothing to say," party spokesperson Jayanthi Natarajan told IANS.

But the party sources said the leadership was discussing the crisis and keeping a watch on the evolving situation as they expected "some statement from DMK leaders in Chennai".

The Congress' Tamil Nadu in-charge Ghulam Nabi Azad could not be contacted but sources told IANS that he unlikely to fly to Chennai "any time soon" to try and resolve the crisis.

Meanwhile, in a kind of boost to the Congress, Samajwadi Party chief Mulayam Singh Yadav said in Lucknow that "as of now" there was no threat to the UPA government after the DMK announced withdrawal of support.

"Why are you all taking the issue so seriously? Such a thing continues to happen in politics…This fight has nothing special about it,'' Mulayam Singh told reporters.

However, he did not say if his party would be joining the government.

The latest crisis has come at a time when the government is battling a severe attack from the opposition over rising prices and a raft of corruption scandals including the 2G scam.

The DMK's A. Raja had to step down as union communications minister in November over allegations of wrongdoing in the allocation of 2G spectrum and is now in jail.

The government received another setback last week when the Supreme Court rejected the appointment of tainted P.J. Thomas as head of the country's anti-corruption body, the Central Vigilance Commission.

The Communist Party of India-Marxist (CPI-M) -- a bitter critic of the UPA -- ruled out any alliance between the Congress and Tamil Nadu's opposition party the AIADMK for the April 13 assembly elections.

There was talk that the Congress may tie up the AIADMK. J. Jayalalithaa's party is likely to have a seat-sharing pact with the Left.

"There is no such indication," CPI-M general secretary Prakash Karat told reporters in Delhi. Karat said that he was in touch with parties with which the CPI-M could tie up for the Tamil Nadu polls.

"We are in the midst of finalising the seat-sharing agreement with the AIADMK, and are in constant touch with parties in Tamil Nadu. As far as the Congress and the DMK are concerned, you will see what will happen," Karat said.