PYONGYANG, North Korea >> Ex-President Jimmy Carter and three other former heads of state embarked Tuesday on a three-day mission to North Korea, where they plan to discuss dangerous food shortages and stalled nuclear disarmament talks.

Children presented flowers to Carter, former Finnish President Martti Ahtisaari, former Norwegian Prime Minister Gro Brundtland and former Irish President Mary Robinson at the airport, and the group was greeted by Vice Foreign Minister Ri Yong Ho, according to Associated Press Television News in Pyongyang.

The former leaders didn’t know ahead of their three-day trip who they would meet with, but said they hoped to have talks with North Korean leader Kim Jong Il and his son and heir apparent Kim Jong Un. The delegation was not expected to speak to the press until it reaches Seoul on Thursday.

Also likely on the agenda is the dismal relationship between North and South Korea that has hampered efforts to restart talks on persuading the North to abandon its atomic weapons ambitions.

Animosity has soared between the neighbors since North Korea allegedly torpedoed a South Korean warship in March 2010, killing 46 sailors. Pyongyang shelled a South Korean island in November, killing two civilians and two marines. The North also revealed a secret uranium enrichment program late last year that would give it a second way to make nuclear weapons.

Before flying from Beijing to Pyongyang, Carter told South Korea’s Yonhap news agency that he didn’t intend to raise the case of Jun Young Su, a Korean-American being held in North Korea, reportedly on charges of carrying out missionary activity. Carter flew to North Korea last year to free another American jailed in Pyongyang.

The U.S. State Department said last month that Carter would not be carrying any official messages.

South Korea reacted coolly to the trip.

"We don’t have high expectations," South Korean Foreign Minister Kim Sung-hwan told reporters Tuesday when asked if the Carter visit might change North Korea’s attitude. "I don’t think it’s necessary for North Korea to talk to us through a third party."

It is not the first time Carter has traveled to North Korea during a period of high tension. In 1994, he met with then-leader Kim Il Sung, Kim Jong Il’s father and the North’s founder, and helped broker a U.S.-North Korea nuclear deal.

He last visited North Korea in August to win the release of imprisoned American Aijalon Gomes, who had been sentenced to eight years of hard labor for crossing illegally into the North from China. Carter did not meet then with Kim, who was on a rare visit to China, his nation’s biggest ally and aid provider.

Carter’s trip comes amid efforts on several fronts to reinvigorate the stalled six-nation nuclear negotiations. China’s top nuclear envoy arrived in Seoul on Tuesday for talks, while a South Korean delegation was to meet with U.S. diplomats in Washington.

North Korea’s nuclear envoy reportedly traveled to Beijing earlier this month to discuss the negotiations, which involve the two Koreas, the United States, China, Japan and Russia.

The former world leaders also said they plan to discuss food shortages in North Korea.

Years of poor harvests, a lack of investment in agriculture and political isolation have left the North severely vulnerable to starvation, with the average amount of food distributed by the government to each person dropping this year from 1,400 calories per day to just 700, according the U.N.’s World Food Program.

Robinson, the former Irish president, said a recent United Nations study based on conditions throughout North Korea classified 3.5 million out of the country’s 24 million people as "very vulnerable" to starvation and that conditions stood to worsen with cuts in food distribution.

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Associated Press writer Kay Seok contributed to this report from Seoul.