North Korean leader Kim Jong Il appeared to be travelling to the eastern city of Changchun Friday on the second day of a visit to China, dpa reported.
A convoy of about 30 vehicles left the Crystal Hotel early Friday in Jilin, a city about 400 kilometres from the North Korean border, South Korea's Yonhap News Agency reported.
The motorway from Jilin to Changun, about 100 kilometres away, was closed Friday for about two hours, officials told the German Press Agency dpa in Beijing.
In the industrial town of Changun, preparations were under way for the visiting leader.
Observers were speculating on the purpose of the trip because it is the first time Kim, who was in Beijing in May, has visited China twice in one year.
It was thought that 68-year-old Kim, who is said to have suffered a stroke in 2008, was preparing to hand power to his third and youngest son.
Kim Jong Un, about whom little is known other than he is thought to be in his 20s, might be accompanying his father, South Korean officials were quoted as saying Thursday.
There was speculation that Kim Jong Il planned to introduce his son to China's communist leaders, North Korea's main political and economic supporter.
Pyongyang's nuclear disarmament was also thought to be on the agenda after Pyongyang walked away from negotiations in 2009.
An envoy from China, which is pushing for a resumption of the talks, last week held a meeting with officials in Pyongyang, which the North's state-run news agency said "reached a full consensus."
North Korea abandoned the six-party talks with the United States, Japan, Russia and South Korea in April 2009 over UN sanctions.
But Pyongyang in July indicated a willingness to return to the table although has not yet proposed dates or venues.
North Korea's number two leader, Kim Young Nam, in a meeting with former US president Jimmy Carter this week, "expressed the will of the DPRK [North Korean] government for the denuclearization of the Korean Peninsula and the resumption of the six-party talks," the North's official Korean Central News Agency said Friday.
Carter arrived in Pyongyang Wednesday to secure the release of a US citizen detained for illegal entry into the communist country. He succeeded and left Friday with the man, but some observers expressed surprise that Kim Jong Il did not stay in North Korea for Carter's visit.
Kim's trip to China was confirmed by neither Pyongyang nor Beijing, but previous visits have been announced only once they are over, reportedly out of security concerns.
It also remained unclear whether Kim was to continue onward to Beijing to meet with Chinese President Hu Jintao.