The Congress in Kerala has decided to seek an explanation from its MP Shashi Tharoor for praising Prime Minister Narendra Modi, who belongs to the rival party BJP.
Mr Tharoor last week came out in support of party colleague Jairam Ramesh, who cautioned against "demonising" PM Modi for every issue as it could make it difficult for the Congress to confront him.
"As you know, I have argued for six years now that Narendra Modi should be praised whenever he says or does the right thing, which would add credibility to our criticisms whenever he errs. I welcome others in opposition coming around to a view for which I was excoriated at the time," Mr Tharoor had said.
The party's chief in Kerala, Mullapally Ramachandran, said the Congress will not "accept" Mr Tharoor's remarks.
"We have decided to seek explanation from Shashi Tharoor and the course of action will be taken based on his explanation. No one should be praising Modi at the expense of the Congress; the party will not accept that," said Mr Ramachandran.
Another Congress MP from Kerala, K Muraleedharan, expressed his disappointment against Mr Tharoor. "The party is really upset with him in Kerala. The BJP is anti-minority. Tharoor has won the elections repeatedly only because of support of people from all sections," Mr Muraleedharan said.
Mr Tharoor, this evening, clarified that he has been a strong critic of the Modi government and urged his partymen to respect his approach.
"I've been a strong critic of the Modi government, and I hope a constructive one. My staunch defence of inclusive values and constitutional principles has won me three elections. I urge my fellow Congressmen to respect my approach even when they don't agree with it," he tweeted.
BJP's Kerala chief Sreedharan Pillai, responding to the Congress's position on PM Modi, said the opposition party is "disintegrating day by day due to infighting".
"And some statements should be seen as positive signs for the BJP. During the last election, anti-BJP wave was created by some by instilling fear in minorities. Now, all that is coming clean. People too must revisit their stand," Mr Pillai said.
Kerala is preparing for by-elections to six assembly seats. The dates are yet to be announced. One of them is an assembly constituency that falls within the Thiruvananthapuram parliamentary constituency, represented by Mr Tharoor.