Massive crowds have gathered outside a hospital in southern India's Tamil Nadu state where a politician who has served as chief minister (CM) five times was admitted on Saturday, reports Reuters.
Muthuvel Karunanidhi (94), is being closely "monitored and treated" in the intensive care unit.
Doctors say he has made some improvement after an apparent urinary tract infection.
But police are struggling to contain emotional crowds desperate for news.
After 50 years as the leader of India's DMK party, he has amassed a huge following in India, and enjoys a god-like status among his supporters.
The 94-year-old politician was first admitted to hospital in the city of Chennai on Saturday night, following a drop in his blood pressure, according to a statement posted on his Twitter account.