A day before the Niti Aayog meeting, four non-BJP Chief Ministers extended their support to Delhi Chief Minister Arvind Kejriwal's sit-in protest at Lt. Governor's office, saying there is a "constitutional crisis" in the state and they will urge Prime Minister Narendra Modi to solve the issue at the earliest.

The Chief Ministers - West Bengal's Mamata Banerjee, Kerala's Pinarayi Vijayan, Karnataka's H.D. Kumaraswamy and Andhra Pradesh's N. Chandrababu Naidu - also accused the Central government of "restricting the federal system", terming it a threat to the nation.

They also said they were denied permission to meet Kejriwal and the Lt Governor Anil Baijal even after having waited for long, asking how was it possible in a "democracy".

"This is a constitutional crisis. But there should never be such crisis due to which a government and the common people have to suffer," said Banerjee at a joint press conference with Vijayan, Kumaraswamy and Naidu.

"We will tell the Prime Minister to intervene in this matter and solve it. Had the President been here, we would have told him too. This is a democracy and that is not how a democracy functions.

"They (the Centre and the Lt Gov) are not allowing the government to function. They (the Kejriwal regime) say they are not able to work. What they will do. Their work has been obstructed and restricted," she said.

To show solidarity to Kejriwal's protest demanding IAS officers to end their non-cooperation with his government, the four Chief Ministers visited Kejriwal's residence, where they met his wife and other members of his family.

"We have come here to show solidarity with Kejriwal. Politics is there in its own place," they said.

"Because of the attitude of Central government this has happened. Centre is restricting the federal system which is a threat to the nation. Everyone is with him (Kejriwal). All the democratic people are with Delhi Chief Minister," Vijayan said.

"We want the issue should be solved and there should not be any fight on this. The mandate of the people of Delhi should be respected," Banerjee said, noting that if such a "small problem" of Delhi can not be solved, how can the country's problems be solved.

"LG is the appointed leader, if not him then to whose doors will one go and knock? They should have solved the matter among themselves. Why did it take so long," she asked and pointed that how the Lt. Governor did not meet Kejriwal who is on protest for six days for even six minutes.

The four Chief Ministers, who had met here to discuss the issue, also wrote a joint letter to Baijal seeking to meet Kejriwal but again verbally denied on the pretext that Baijal is out.

"We tried our best as per the Constitution to seek permission from the LG to meet Arvind and him. He (the Lt Gov) has not given us permission. If he has not given us permission, then don't consider us so small that we are like street beggars. Even we have due respect," Banerjee said.

"We waited for three-four hours to meet the Lt. Governor. In a democracy, how can I not meet a Chief Minister and an Lt. Governor in a democracy. This is not democracy."

In the evening, Banerjee attended a meeting at Andhra Bhawan with her counterparts Vijayan, Kumaraswamy and Naidu.

The four Chief Ministers met shortly after Baijal declined permission to Banerjee to meet Kejriwal. She had planned to go to the protest site -- Lt. Governor's residential office -- along with Naidu.

Informed sources said the four Chief Ministers were planning a strategy on how to strengthen Kejriwal's hands.

Kejriwal, along with Deputy Chief Minister Manish Sisodia and Cabinet ministers Satyendar Jain and Gopal Rai, is camping at Raj Niwas since Monday demanding a direction to the IAS officers working in the Delhi administration to end their undeclared strike.

He also wants the central government to approve his government's proposal to deliver ration to the poor at their houses.