The condition of ailing Congress leader K Karunakaran continued to be critical on Thursday and was on ventilator support, hospital sources said.
Ventilator support was resumed on Wednesday for the 93-year old leader after he suffered acute breathing trouble following a stroke at the Ananthapuri Hospital, where he was admitted on December 10.
After remaining serious for several days, his condition had improved earlier this week and was taken off ventilator. But he had been put back on ventilator support since Wednesday.
Karunakaran was admitted to hospital with severe breathing problem and fever.