North Korea's nuclear programs were on the agenda on Monday as the Chinese and South Korean presidents met for a summit amid recent angry rhetoric from Pyongyang.

Chinese President Hu Jintao and South Korean President Lee Myung-bak began about 30 minutes of one-on-one talks to be followed by a broader meeting with foreign affairs, security and economic officials attending, according to the presidential Blue House.

Hu arrived earlier for the two-day state visit, flush with his country's success in hosting its first Olympic Games, which concluded on Sunday.

He was given a red-carpet welcome at a military airport by South Korean Foreign Minister Yu Myung-hwan before heading into the capital to begin the summit.

Later, about 10 protesters in downtown Seoul held up a sign reading "Grant refugee status to North Koreans."

China does not recognize North Koreans who enter the country as refugees, rather viewing them as economic migrants.

China and North Korea have a treaty that calls for the repatriation of North Koreans caught crossing their shared border. Human rights advocates in South Korea say North Koreans face persecution if they are sent back.

Hu and Lee were to hold in-depth consultations on "advancing the six-nation talks" aimed at ending North Korea's nuclear programs, according to comments posted on South Korea's presidential Web site earlier.

China, North Korea's key ally and main aid donor, has chaired numerous rounds of disarmament talks since 2003 on the North's weapons programs. The talks — which also involve the US, the two Koreas, Russia and Japan — have produced a landmark aid-for-disarmament deal.

In June, North Korea demolished its nuclear reactor's cooling tower and submitted its long-delayed nuclear declaration. The North, however, remains at odds with the US over how to verify the declared nuclear programs.

North Korea has accused Washington of delaying its removal from a US terrorism blacklist. Washington has said it will drop North Korea from the list only after it agrees to a full nuclear verification plan.

North Korean state media carried a series of dispatches criticizing the US last week and blasting US-South Korean computer-simulated war games.

The North's Foreign Ministry said Pyongyang would bolster its "war deterrent" — a euphemism for its nuclear programs — amid "military threats" posed by the US.

At the summit in Seoul, Hu and Lee were also expected to discuss action plans for the "strategic cooperative partnership" pledged at their first summit in Beijing in May.

The new partnership includes dialogue between their foreign ministries and cooperation in areas such as trade, environmental protection and nuclear energy.

The two leaders are scheduled to sign several memorandums of understanding on such issues as cooperation in energy and high-tech fields, according to Lee's office.

China is South Korea's largest trading partner, with two-way trade volume reaching $145 billion last year.

The two leaders may have occasion to congratulate each other on their countries' respective Olympic achievements. China won 51 gold medals, the most of any nation competing. South Korea, meanwhile, racked up its best ever performance, taking home 13 golds, including its first in baseball.

The official China Daily newspaper reported that Hu was scheduled to travel to Tajikistan on Tuesday to attend the summit of the Shanghai Cooperation Organization, a security forum that includes China, Russia and Central Asian nations.

He was set to travel to Turkmenistan on the last leg on his three-nation tour, the paper said.