Dr. Lee Jong-wook, chief of the World Health Organization (WHO), died early on Monday after undergoing emergency surgery for a blood clot at his brain over the weekend.

His death was announced at the opening of the 59th World Health Assembly here.

Dr. Lee, 61, who took over as director-general of the WHO in 2003, fell ill on Saturday afternoon while attending an official function in Geneva.

He was taken to Geneva's Cantonal Hospital and underwent surgery for a blood clot in his brain.

"I am sorry to tell you that Dr. Lee Jong-wook, director-general of the WHO, died this morning," Spain's Health Minister and President of the World Health Assembly Elena Salgado told the opening session of the agency's annual assembly.

Lee "was an exceptional person and an exceptional director general," Salgado said.

Dr. Lee, a national of the Republic of Korea, has worked for WHO for 23 years at country and regional levels and at WHO Headquarters in Geneva.

Source: Xinhua