North Korean leader Kim Jong-il is suffering from pancreatic cancer, South Korea's cable news network YTN reported Monday, quoting unidentified intelligence sources in South Korea and China.

Kim, 67, was diagnosed with the cancer around the time he collapsed by a stroke last summer, YTN said.

Kim's health has been the object of intense media speculation due to concerns about instability and a possible power struggle within the reclusive communist country.

Recent photos showed that Kim looked wearier and older than before.

His third and youngest son, Jong-un, has reportedly been picked as Kim's heir but the North Korean government has yet to confirm it.