Cambodia's ailing former king, Norodom Sihanouk, has left the country for what is being described as routine medical testing in China.

The 88-year-old monarch, who remains a revered figure in his homeland, has undergone numerous rounds of testing and treatments in China since first being diagnosed with cancer in the early 1990s. He also suffers from diabetes and hypertension.

The king and his wife left Phnom Penh for Beijing Wednesday. Details of his China itinerary have not been disclosed.

Sihanouk abruptly quit the throne in 2004 in favor of his son, citing old age and health concerns.