The condition of ailing Congress leader K Karunakaran turned critical on Wednesday and he was put on ventilator support after suffering astroke.

Ventilator support resumed for the 93-year-old leader in the morning after he suffered acute breathing trouble following a stroke, said a medical bulletin issued by Aanathapuri Hospital, where the former Kerala chief minister has been under treatment since 10th December.

However, his heart and kidneys were functioning satisfactorily for the time being, the bulletin said.

Karunakaran was under close observation of a team expert doctors and being given medicines so that his blood pressure stabilises.

After remaining serious for several days, his condition had improved earlier this week and was taken off ventilator.

Karunakaran was admitted to the hospital with severe breathing problem and fever on 10th December.