The condition of veteran Marxist leader Harkishan Singh Surjeet, who was admitted to a New Delhi hospital a fortnight ago with an acute respiratory problem, remained critical on Tuesday.

"He is responding to painful stimuli. There was occasional blinking of the eye and jaw movement. We have reduced his ventilator support as he is maintaining good oxygen saturation," said Dr Purushottam Lal, a cardiac surgeon at the Metro hospital.

"Considering his age," Lal said, "It is difficult to predict that he will recover."

Leader of Opposition in Lok Sabha L K Advani visited the hospital today morning to enquire about the condition of the 92-year-old ailing leader.

Surjeet, who was admitted on May 6 to the hospital with cardiac respiratory arrest, slipped into a coma on May 16.

Surjeet, a former general secretary of the Communist Party of India - Marxist, was not included in the CPI-M Politburo at the party's 19th congress in April this year, due to failing health. He was instead designated as Special Invitee to the Central Committee.