The Nationalist Congress Party, a key UPA constituent with nine Lok Sabha members, threatened to quit the government on Thursday, protesting against party chief Sharad Pawar having been denied the second most important slot in the cabinet after Pranab Mukherjee's resignation.
Pawar and his colleague, heavy industries minister Praful Patel, boycotted the cabinet meeting this evening within hours of voting for Mukherjee in the presidential election.
But the Congress declined comment, saying it was a matter purely related to the government's functioning.
"Our party is likely to hold a meeting tomorrow (Friday) in which all issues will be discussed," said NCP spokesperson DP Tripathi.
NCP sources, however, said they were ready to resign rather than being "repeatedly humiliated" by bigger parties in the alliance - a clear hint of unhappiness with the Congress.
"In case it (NCP) is not given due importance by the Congress party…there is no point in hanging on," said a party leader.
But both sides denied reports of Pawar and Patel having sent in their papers to Prime Minister Manmohan Singh.
Though the NCP was careful in choosing the words for its official response, it was clear that the party decided to utilise the denial of the number two slot for beginning the process of "phased and gradual disengagement" from the alliance.
Tripathi said the NCP had been demanding a coordination committee since eight years to discuss running of the coalition government.
"We should be given the same treatment which is reserved for the DMK and Trinamool Congress."
The first signs of trouble between the Congress and the NCP - coalition partners in Maharashtra for 13 years - surfaced when Pawar stayed away from the UPA meeting on July 14 to finalise Hamid Ansari's candidature as vice-presidential nominee.
Besides Pawar's unhappiness over the Congress decision of not according him the number two status, his party appears to have added a few more issues to its list of woes - one of them is Pawar was not consulted on of governor appointments, not even for Maharashtra, his home state.