Chennai: O Panneerselvam, J Jayalalithaa's close aide, was sworn in as Tamil Nadu Chief Minister on Tuesday, hours after the AIADMK leader died at Chennai's Apollo Hospital. She was 68.

Jayalalithaa, one of the country's most powerful and popular politicians, suffered a cardiac arrest in the hospital on Sunday where she was admitted since September 22. She was put on life support systems and her condition was said to be very critical.

Mr Panneerselvam, 65, a staunch Jayalalithaa loyalist, had earlier stood in twice as chief minister when she had to step down. He was also given charge of the eight ministries she personally supervised and chaired cabinet meetings since 'Amma', as known to millions of her followers was hospitalised.

Mr Panneerselvam kept a picture of Jayalalithaa on the dais before taking the oath. He was sworn in around 1.15 AM by Governor Ch Vidyasagar Rao at the Raj Bhavan. 31 ministers, all of them members of the previous Jayalalithaa cabinet, also took oath in a simultaneous swearing-in.

Lawmakers from Ms Jayalalithaa's AIADMK had a short while earlier chosen Mr Panneerselvam to lead them in the state assembly.

Ms Jayalalithaa's body has been shifted from the hospital to her Poes Garden residence. Her body will later be placed at Chennai's Rajaji Hall for the public to pay their respect.

A seven-day mourning has been declared in Tamil Nadu. Schools and colleges will be closed for three days.