Top Liberation Tigers for Tamil Eelam negotiator Anton Balasingham was on Sunday airlifted from Sri Lanka's rebel-held north and taken to Colombo for urgent medical treatment, the Norwegian embassy said.
Balasingham arrived in Sri Lanka six days ago to discuss the LTTE decision to boycott peace negotiations with its chief Velupillai Prabhakaran.
Before that he had a kidney transplant in Norway and his condition was further complicated by diabetes.
On Sunday morning, the LTTE informed the Norwegians, who are trying to broker peace in the country, that Balasingham needed 'post-transplant' medical treatment, the embassy said in a statement.
A Sri Lanka air force helicopter brought Balasingham (64) out of Kilinochchi, 330km north of Colombo.
Balasingham will spend the night at a location near the Colombo airport before leaving the island on Monday for London to consult his doctors, the sources said.
"Balasingham will leave Sri Lanka as soon as possible, but he has expressed a desire that his absence should not prevent scheduled meetings from taking place," the embassy statement said.
Balasingham was due to meet with Norwegian Foreign Minister Jan Petersen on Thursday in Kilinochchi.
The embassy said Petersen would go ahead with the meeting with the LTTE leadership.