Al-Megrahi, whose family expressed concern about his condition, has been treated for prostate cancer in an intensive care unit of the Tripoli Medical Center for the past week.
Officials said al-Megrahi was unable to speak for long periods. He was receiving oxygen and heavy doses of medication while under constant medical supervision, The Daily Telegraph reported.
"He is in a bad way," a Libyan official said. "He is unable to speak to anyone."
Al-Megrahi served eight years of a life sentence for the 1988 terrorist attack that blew up Pan Am Flight 103 over Lockerbie, Scotland, killing 270 people on the jumbo jet and on the ground. He was allowed to be transferred to Libya for humanitarian reasons.