The condition of 95-year-old ailing Communist Party of India-Marxist patriarch Jyoti Basu deteriorated on Saturday, doctors attending on him said.

"There has been deterioration in his general condition. He has developed fluid retention, drop in urine output and he is drowsier. This signifies multi-organ involvement," private AMRI Hospital Executive Director D N Agarwal told media persons.

Asked if this was a sign of multi-organ failure, he said, "Please don't confuse between involvement and failure."

He said Basu, who was admitted to the hospital on January one with breathing problems, was on partial ventilation and the medical board was constantly monitoring his condition.

Basu had been put on full ventilation last on Friday night as a precautionary measure.

The medical board would meet again at between 6:00 pm to 7:00 pm and the next medical bulletin "may be delayed till 8:00 pm", Agarwal said.

Left Front chairman Biman Bose, Finance minister Ashim Dasgupta, former Lok Sabha speaker Somnath Chatterjee and Basu's son Chandan were at the hospital.