Mitra said he was willing to contest the coming Lok Sabha polls on a Congress ticket if the party high command so desired.
"We (the Trinamool Congress) came to power by making promises. We had said we want to free democracy from partycracy. But now, we have autocracy. The language used by the leadership is an echo of Hitler's Nazi Germany. They are threatening to cut off limbs, skin people alive. But there is no protest," Mitra said.
"We had said we want change, not retaliation. But there are many instances where retaliation has taken place. The condition in schools and colleges has become really bad," said the 70-year-old leader, who won from the Diamond Harbour Lok Sabha constituency in South 24-Parganas district in 2009 on a Trinamool ticket.
The Congress leadership has earlier announced that Mitra - a former state Congress president - will rejoin the party Jan 21.