North Korea marked the 65th birthday of leader Kim Jong-il on Friday amid progress in ending its nuclear programs and lingering speculation abroad over who will eventually succeed him.

Kim's birthday is one of North Korea's most important national holidays and one in which the personality cult he inherited from his father, the country's founder Kim Il Sung, is clearly visible.

'In order to make it a good birthday, I hope North Korea will implement what the partners have decided at the six-party talks.'—Japanese Prime Minister Shinzo Abe

North Koreans usually receive perks such as extra food, but it remains unclear whether the country can afford such largesse this year, given chronic food shortages and UN sanctions imposed over its Oct. 9 nuclear test.

"Holidays in North Korea mark occasions on which the leadership is obligated to show tangibly its ability to care for the people," said Scott Snyder, a senior associate at the Asia Foundation in Washington who served as chief of its Seoul office.

The North Korean "leadership will be able to perform at a higher level in this area" amid reduced tensions with the international community following this week's nuclear agreement, Snyder added.

The breakthrough deal reached in Beijing on Tuesday requires the hardline Communist regime to shut down its main nuclear reactor and allow UN inspectors back into the country within 60 days.

In return, the energy-starved country would receive aid equal to 45,000 tonnes of heavy fuel oil from the other countries participating in the six-party talks — the United States, South Korea, Russia, China and Japan.

"Psychologically, Kim Jong-il would not be in a sombre mood," said Koh Yu-hwan, a North Korea expert at Seoul's Dongguk University, citing the nuclear deal and the prospect of winning economic aid.

Still, North Korea kept up its anti-American rhetoric and urged its people to rally around Kim, known as the country's "dear leader."

In a joint letter of congratulations to Kim on his birthday, North Korea's cabinet, ruling party, parliament and military vowed to defend the country from the U.S. and "mercilessly destroy and mop up the aggressors if they dare to ignite a war."

In the runup to the birthday, North Korean media have reported a festive mood in the country, with arts performances being held as well as exhibitions in the capital Pyongyang of the Kimjongilia — a red flower cultivated to bloom around Kim's birthday.

Kim has yet to name a successor, prompting speculation abroad about who might rule the reclusive country and whether Kim will designate one of his sons as the next leader — continuing the world's only communist dynasty.

Japanese Prime Minister Shinzo Abe, whose country has been at odds with North Korea over the abductions of Japanese citizens to be trained as spies, used Kim's birthday as an opportunity to urge him to follow through on the Beijing nuclear agreement.

"In order to make it a good birthday, I hope North Korea will implement what the partners have decided at the six-party talks," Abe told reporters in Tokyo Thursday evening.

Russian President Vladimir Putin and China's Communist Party sent messages to congratulate Kim on his birthday, KCNA reported Friday.