Updated

North Korea has launched a public propaganda campaign to prepare its people for the succession of Kim Jong Il's youngest son as leader, a news report said Sunday.

North Korea has mentioned Kim Jong Un by his full name — which it had not done in the past — and his qualifications in broadcasts through speakers installed in each house, Yonhap news agency reported, citing an unidentified source on North Korean affairs.

The broadcast campaign was launched in Pyongyang about two months, but it was not clear if it had been extended to other parts of the country, Yonhap said.

North Koreans are obligated to install speakers in their homes to listen to broadcasts on policy of the ruling Workers' Party and its propaganda, according to North Koreans who have defected to the South.

Kim, 67, believed to have suffered a stroke last year, has not publicly named his successor but is widely reported to be grooming the 26-year-old to take over.

However, North Korea's No. 2 leader Kim Yong Nam last week told Japan's Kyodo news agency that Kim Jong Il is in good health and denied that Kim Jong Un had been named successor. He dismissed that as speculation by foreign media aimed at harming the North.

The speculation has also eased somewhat since Kim Jong Il met former President Bill Clinton last month in a landmark meeting that led to the release of two detained U.S. journalists.

Kim, who has three sons, has controlled the reclusive, impoverished nation of 24 million with absolute authority since he assumed power upon his father Kim Il Sung's death in 1994, leading to concern about instability in the nuclear-armed nation and a power struggle if he were to die without naming a successor.

Yonhap said North Korea has designated the 2012 birth centennial of Kim Il Sung as the date for an official announcement for the succession as long as the current leader remains healthy.

In other moves seen as promoting Kim Jong Un, the North has released a song said to symbolize him being groomed as heir, Yonhap said.

The news agency also cited a South Korean visitor as saying that a guide at a North Korean tourist site last month referred to a visit by Kim Jong Un with his father to the site. The name of the site and other details were not given. Previously, such references by tourist guides were confined to Kim Jong Il or his late father Kim Il Sung, the North's founder, it said.

South Korea's spy agency declined to comment on the Yonhap report.