TRIPOLI, Libya -- The convicted Lockerbie bomber Abdel Baset al Megrahi has been hospitalized in Tripoli, where he remained in critical condition Saturday, a source close to Megrahi's family said.

"Abdel Baset has been in the hospital since yesterday [Friday] and his condition is critical," the source told AFP, adding that Megrahi's relatives were by his bedside.

Megrahi was convicted in a Scottish court in 2001 over the 1988 bombing of a Pan Am jet. Some 270 people died in the attack.

The 60-year-old was released on compassionate grounds in 2009 and allowed to return to Libya, with doctors saying at the time that he was suffering from terminal cancer and had only three months to live.

Megrahi was greeted as a hero upon his return to Libya after he served eight years of a minimum 27-year jail term for his role in the bombing.

Britain's prime minister David Cameron criticized the release at the time, calling it a "terrible mistake." The fact that he has survived so long after his release has also led to anger in the US and Britain.

In August 2011, following the revolution which toppled Moamar Ghadafi, Megrahi's brother Abdel Nasser said at the family home in Tripoli that Megrahi was "in and out of a coma."

Megrahi had appeared on TV at a rally in Tripoli in July 2011 in support of Ghadafi, leading Britain's foreign secretary William Hague to respond, "The appearance of Mr. al Megrahi on our television screens is a further reminder that a great mistake was made when he was released."

All 259 passengers, mainly Americans, and crew, died when the Pan Am flight exploded over the town of Lockerbie in southern Scotland in December 1988. A further 11 people on the ground died in the incident.

Megrahi was convicted of 270 counts of murder by a panel of Scottish judges, but he has consistently proclaimed his innocence in the bombing.

In a statement issued following his release in 2009, he said, "I say in the clearest possible terms, which I hope every person in every land will hear -- all of this I have had to endure for something that I did not do."