Senior Congress leader P Chidambaram on Tuesday slammed the Uttar Pradesh government and said that party general secretary Priyanka Gandhi Vadra's detention is "completely illegal and utterly shameful".

Priyanka Gandhi Vadra was detained while she was on her way to Lakhimpur Kheri on Monday.

"It's completely illegal and utterly shameful. She was arrested at 4:30 am, before sunrise by a male police officer. She has not been taken to a judicial magistrate so far yet," said Chidambaram.

Slamming Bharatiya Janata Party (BJP)-led Yogi Adityanath government in Uttar Pradesh, senior Congress leader further said, "Law and order in UP means Mr Aditynath's law and order which is not the criminal procedure code."

He went on to allege, "This is a violation of the fundamental right of Priyanka Gandhi and other detainees. CM Yogi Adityanath and BJP are making India an unfree country."

Uttar Pradesh Police on Tuesday registered an FIR against Congress general secretary Priyanka Gandhi Varda and 11 others for 'disturbing the peace' in the state.

According to Hargaon Police station SHO Brijesh Tripathi, a case has been filed against 11 including Priyanka Gandhi Vadra, Devindra Hooda and Ajay Kumar Lallu under Section 107/16 of the Indian Penal Code (IPC).

Earlier in the day, Congress leader Priyanka Gandhi Vadra had claimed that she has been detained for the last 28 hours without any order or FIR.

As many as eight people died in the Lakhimpur Kheri incident on Sunday.

The Samyukta Kisan Morcha (SKM) had on Sunday issued a statement regarding the incident claiming the death of four farmers and alleged that one of the four farmers was shot dead by Union Minister of State for Home Ajay Mishra Teni's son, while the others have been allegedly run over by the vehicles of his convoy.

Meanwhile, refuting SKM's allegations, MoS Teni said that his son was not present at the spot, adding that some miscreants merged with protesting farmers and pelted the stones on the car which lead to the 'unfortunate incident'.