Following an order of the Allahabad High Court, Dr Kafeel Khan was released from Mathura jail late on Tuesday night, his lawyer said.

"Mathura jail administration informed at around 11.00 pm that Dr Kafeel will be released, and at around midnight, he was released," Khan's lawyer Irfan Ghazi told PTI.

The Allahabad High Court on Tuesday quashed Khan's detention under the National Security Act and ordered his immediate release.

The bench, comprising Chief Justice Govind Mathur and Justice Saumitra Dayal Singh, passed the order on a petition filed by Khan's mother Nuzhat Parveen.

The petition alleged that Khan was granted bail in February by a competent court and he was supposed to be released on bail. However, he was not released for four days and the NSA was subsequently invoked against him. Hence, his detention was illegal, the petition argued.

Khan was in jail since January after he delivered an allegedly provocative speech at the Aligarh Muslim University (AMU) during the anti-Citizenship (Amendment) Act (CAA) protests in December last year.