Doctors in Hong Kong operated Friday on Jason Leung, the Toronto-area teen who was injured in Monday's hostage-taking in Manila, to remove part of his skull and insert a monitor to track swelling in his brain.

Jason Leung, who was injured during this week's hostage-taking on a bus in Manila, has undergone surgery for a serious head injury. (Courtesy of Ameen Khwaja)

In the 12-hour hostage-taking on a tourist bus in the Philippines, Leung, 18, suffered a depressed skull fracture and was left in a coma. He was transported from Manila to Hong Kong's Tuen Mun Hospital on Thursday.

Leung's father, Ken, 58, and two sisters, Doris, 21, and Jessie, 14, were among eight tourists killed in the hostage-taking, which ended when police shot the man who had commandeered their bus — a former police officer distraught over his dismissal.

Dr. Dawson Fong, a neurosurgeon, said the procedure was successful. However, he said Leung's fever went up following surgery and he was being treated with antibiotics.

"His intracranial pressure has stayed at an acceptable level since the surgery. And we can see since we created an opening in his skull, it's been easier to control his vital signs, so he is relatively stable," Fong said.

Fong was quoted in a media report as saying that if everything goes smoothly, the swelling in the brain should stabilize within a week or 10 days.

Leung was born in Canada and graduated in June from Bronte College, a private boarding school in Mississauga, just west of Toronto.

Hong Kong leader Donald Tsang visited Jason and his mother, Amy Ng, on Friday.

"I hope Mrs. Leung will take care of herself too besides nursing Jason. She was very peaceful just now. She even told me not to worry," Tsang said after his visit.

Tsang also attended a memorial for Ken Leung that drew a reported 1,200 people.

The hostage-taking and the tourists' deaths has drawn an outpouring of emotions from Hong Kong and China. Many Chinese officials have expressed anger at the way they say Philippine security forces handled the hostage-taking.