Sonia, Rahul mourn Jayalalithaa's demise
In her condolence message, Sonia Gandhi said: "I am deeply grieved to learn of the passing away of Selvi J Jayalalithaa."
Sonia said Jayalalithaa had "a unique and deep empathy with the needs and hopes of the people."
She said Jayalalithaa's policies were meant to improve the lives of the people of her state.
"Whether it was her welfare schemes for the rural and urban poor, her swift relief measures in the aftermath of tsunami, or her vision for Tamil Nadu's industrial development, her leadership qualities and administrative abilities were truly outstanding," said the Congress supremo.
Her son Rahul Gandhi stated: "We lost a great leader today. Women,farmers,fishermen & the marginalised dreamt through her eyes.We will miss Jayalalithaa ji,Amma to millions."
The 68-year-old leader, who was also a top heroine of Tamil film industry before she joined politics full time, was declared dead by the Hospital which said the end came at 1130 pm.
"Our beloved leader, The Iron Lady of India Puratchi Thalaivi Amma is no more," tweeted All India Anna Dravida Munnetra Kazhagam (AIADMK).
Jayalalaithaa's AIADMK supporters had assembled outside the hospital all through the day.
The supporters at one point broke barricades in front of the hospital. Heavy police deployment has been made.
Jayalalithaa was in Apollo Hospital since Sept 22 and then suffered a cardiac arrest on Sunday evening and was put on an extracorporeal membrane heart assist device, a life support system that aids heart and lung functioning.
Jayalalithaa Jayaraman was born on 24 February 1948 and was popularly and fondly referred to as Amma and Puratchi Thalaivi by members in her party.
While she last assumed the office of CM in 2015, she previously served as Chief Minister from 1991 to 1996, in 2001, from 2002 to 2006 and from 2011 to 2014.