BEIRUT - Shiite Islam's most revered cleric, Grand Ayatollah Ali Sistani, was headed for London for medical treatment Friday amid fierce fighting in his Iraqi base of Najaf, officials at Beirut airport and at the Al-Khoei foundation in London said .
Sistani, 73, arrived in the morning from Baghdad and flew out on a Middle East Airlines flight for London at 11:30 am (0830 GMT), the officials said, without elaborating on his state of health.
The Al-Khoei foundation, a Shiite institution based in London with which Sistani has close links, said that the cleric was expected to arrive at London's main Heathrow airport at 2:00 pm.
"I've heard three of his arteries are blocked," said Al-Khoei spokesman Eagle Abdlemalik. "I can't say how long he is going to stay."
"He was persuaded to leave Najaf obviously because of his critical state of health," the spokesman said, adding that Sistani would be residing at his offices in north London during his stay in Britain.
The cleric met parliament speaker Nabih Berri, who heads the Lebanese Shiite faction Amal, during his stopover, the officials added.
Sistani is regarded by the US-led coalition as a key moderating force among Iraq's Shiite majority.
Under his influence, the mainstream religious leadership in Iraq's Shiite holy cities has distanced itself from radical leader Moqtada Sadr, whose militia has been engaged in fierce battles with US-led troops since Thursday.
Iraqi national security adviser Muwaffaq al-Rubaie said that Sistani's trip to London had been planned for weeks.
Sistani, who is not suffering from a terminal illness, was accompanied by his son, doctor and an assistant, he added.
The senior cleric is expected to stay in London for up to a week.
"I can tell you that I was intimately and personally involved in this trip. It has been organised for several weeks. I took him from Najaf and sat him inside the plane... I took him from door to door".
Rubaie, a doctor once exiled in London, said he had chosen a London medic for Sistani based on his knowledge of the British health care system.
Any suggestion that Sistani was bandied out of the country for his own safety while US and Iraqi forces crush Sadr's militia was "absolutely ridiculous," Rubaie said.