North Korea's communist party is getting ready to hand over more authority to another member of its ruling dynastic family in September.

The Workers' Party of Korea will have a meeting of its central political bureau "for electing its highest leading body," the state-run Korean Central News Agency said.

The meeting, expected in September, is a signal that ailing leader Kim Jong Il may be getting ready to take a back seat in favor of his third son, Kim Jong Un, whom he has been grooming for higher office for several years.

Kim Jong Un, 27, increasingly has been accompanying his father on internal trips within the secretive country.

Last year there was speculation that the Swiss-educated Kim Jong Un was already leading the Workers Party of Korea as part of his eventual rise to replace his father.

Kim Jong Un reportedly attended the English-language International School of Bern under a false name in 1998 and few photographs of him exist.

His father, Kim Jong Il, took power in 1994 upon the death of his father, Kim Il Sung, a devoted communist who ruled North Korea from its founding in 1948. The "Great Leader," so-called by state media, established the cult of personality that persists within the secretive and economically failing country. He died age 82.

Kim Jong Il is believed to have suffered a stroke in 2008 and is thin and frail after many months of not appearing in the media. He also may have pancreatic cancer, a fatal disease from which death usually is only a couple years after diagnosis, South Korean intelligence service reports said last year.

But the young Kim Jong Un may not have a completely free path to the top when he father dies.

Last July South Korean intelligence services said Jang Song Taek, North Korea's No. 2 man, might seize power after the expected death of Kim Jong Il.

Jang, 63, is head of the National Defense Commission, another powerful body and he may not be happy with taking orders from a 27-year-old man. Jang, who is also Kim Jong Il's brother-in-law, is said to back Kim Jong Nam, 39, Kim Jong II's eldest son who has been passed over as future leader.

Jang studied in Moscow between 1969 and 1972 and steadily rose up government ranks to be vice director of the Workers' Party of Korea. Despite being purged from the job in late 2004, he re-emerged to accompany Kim Jong Il on a trip to China in 2006. He was elected head of the National Defense Commission, the de facto ruling body within the military regime, in April 2009.

The expected September meeting will take place at a time of increasing tensions with South Korea and a plummeting relationship with the United States. These are two good reasons, according to some analysts, why North Korea's communist party wants to be ready with solid, and younger, leadership.

At the same time as announcing the September meeting of the communist party, North Korea threatened to increase the punishment for an imprisoned American found guilty of entering the country illegally.

Aijalon Mahli Gomes, 30, is a former English teacher in South Korea. He was arrested in January after crossing from China.

Central to the threat is the international pressure, led by South Korea and the United States, being put on North Korea over its alleged sinking of a South Korean naval patrol boat in March.

North Korea, as the Democratic People's Republic of Korea, has repeatedly denied it fired a torpedo at the Cheonan, which sank in disputed waters off the west coast near the demilitarized line that has separated the two Koreas since the 1953 cease-fire.

"The U.S. is escalating the campaign to put international pressure upon the DPRK while persistently antagonizing the DPRK over the Cheonan case. Such moves have gone beyond the tolerance limit," an article in the Central Korean News Agency said.

"The U.S. government is requesting the DPRK to leniently set him free from a humanitarian stand but such thing can never happen under the prevailing situation and there remains only the issue of what harsher punishment will be meted out to him."