After a troubled worldwide trip the Beijing Olympic torch relay got under way on Monday in the capital of communist North Korea, where thousands were mobilised to show support for close ally China.

TV footage showed crowds dressed in their best clothes packing the streets of Pyongyang as the torch began its 20-kilometre relay route. It was the first time the Olympic flame had been carried in North Korea.

"Cheer for Beijing, Cheer for Pyongyang and Cheer for the Olympic Games," read one banner.

In some other cities, the relay has sparked rowdy protests against China's policies on Tibet and other issues. North Korea clamps down sharply on any dissent and the Pyongyang leg was guaranteed to run smoothly.

Reclusive leader Kim Jong-Il was absent from the launch ceremony at the Tower of the Juche Idea — named after the impoverished state's guiding ideology of juche or self-reliance.

De facto head of state Kim Yong-Nam handed the torch to the first runner, a hero of one of the nation's greatest sporting triumphs.

"This will be a beautiful memory that will be left with me," Pak Du-Ik, 71, told Japan's Kyodo News after his 250-metre jog. "I will never forget this."

Pak scored the only goal in North Korea's famous 1-0 win over Italy which secured their place in the 1966 World Cup quarter-finals.

The last runner was to be Jong Song-Ok, who won the marathon at the 1999 World Athletics Championships.

The torch has been dogged by demonstrators since the Olympic flame was lit last month. Critics of China's crackdown in Tibet and its general human rights record severely disrupted the Paris and London legs.

Organisers in many other countries have been forced to surround the torch with unprecedented security to ensure a smooth passage.

North Korea has promised to "astonish the world" with its handling of the relay and has criticised the overseas protests.

Radio Pyongyang on Monday slammed the demonstrations as "an open challenge to the spirit and charter of the Olympics," according to Seoul's Yonhap news agency.

During the South Korean leg on Sunday, demonstrators including North Korean defectors staged protests against China's forced repatriation of refugees from the North.

There were sporadic clashes in Seoul between the protesters and thousands of Chinese students. The Seoul government on Monday expressed "strong regret" to Beijing's ambassador about the behaviour of some of the students.

China sends back all those North Koreans it catches as economic migrants, a policy strongly criticised by rights groups. Refugees face severe punishment, or even a death sentence in some cases, on their return.

In Pyongyang, men in dark suits and women in traditional hanbok gowns waved artificial bunches of kimjongilia, a national flower named after the leader, as the relay got under way at 10.15 am (0115 GMT).

Banners reading "Beijing 2008" were hung on both sides of the route.

A total of 80 people were due to carry the torch along the route, which ends at Kim Il-Sung Stadium at around 3pm.

Official media have said they include "officials of merit," famous athletes, working people, overseas Koreans and foreign residents.

Kyodo said almost three-quarters of the runners are North Koreans and the rest are Chinese nationals, including ambassador Liu Xiaoming.

The torch had arrived in North Korea early on Monday by chartered plane direct from Seoul, to a welcome from nearly 1000 locals and Chinese students.

The flame will be taken to Vietnam after North Korea and then to Hong Kong and Macau, before starting the final leg of the relay in mainland China.

AFP