There are reports that North Korean leader Kim Jong-il has traveled to China.
South Korean media say Kim Jong-il's personal train crossed into China at the northeastern Chinese city of Dandong Monday. The detailed reports say the North Korean leader is spending the night in the city of Dalian before heading to Beijing.
Officials at the Chinese Foreign Ministry and at the North Korean embassy in Beijing could not be reached because of a holiday in China.
Security was reported to be heavy at the North Korean border, but there was no apparent tightening in Beijing, where Mr. Kim is believed to be heading. Some people in the Chinese capital, like 28-year-old bank employee Tao Ye, welcomed the possibility of the visit.
Tao says he hopes China can help North Korea develop and strengthen its economy. He also pointed to the strong feelings Chinese and North Korean people share.
The trip to China would be the North Korean leader's first in four years and Mr. Kim's first trip abroad since a suspected stroke in 2008.
China is North Korea's largest trading partner and main political ally.
Analysts say Mr. Kim may be heading to China to seek financial aid, following a botched North Korean currency reform at the end of last year that worsened inflation and sparked civil unrest. The isolated country is also under pressure because of United Nations sanctions imposed after Pyongyang conducted a nuclear test a year ago.
Yang Moo-jin is a professor at South Korea's University of North Korean Studies.
Yang says he thinks the North Korean leader's visit is aimed at discussing cooperation with China on strengthening economic ties, nuclear disarmament talks and "the Cheonan incident."
The Cheonan incident refers to the unexplained sinking of a South Korean navy ship in March. Seoul suspects Pyongyang was to blame. China has expressed condolences for the lives lost in the incident, but has refused to take sides.
The six-party talks aimed at ending North Korea's nuclear weapons programs have been stalled for more than a year, because of a boycott by Pyongyang.
The talks bring together the United States, North Korea, China, South Korea, Japan and Russia.