The hospital is likely to issue a bulletin on the condition of the 94-year-old leader.
Kauvery hospital had said yesterday evening that Karunanidhi's condition had "declined" and keeping his vital organs functioning remained a "challenge". It had said the next 24 hours could be crucial.
Meanwhile, hundreds of DMK cadres have collected outside the hospital in downtown Alwarpet and the crowd is swelling by the minute.
Many were seen weeping and chanting slogans hailing the leader. A woman supporter was seen fainting and being helped by others who sprinkled water on her face.
Security has been enhanced at the hospital and the Gopalapuram residence of the nonagenarian leader.
As concerns over Karunanidhi's condition mounted, a general alert was sounded across the state. Security was stepped at major installations.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)