BEIJING — The Olympic torch was re-lit today at an elaborate ceremony that signaled the start of a round-the-world relay that is expected to be a lightning rod for protests against China's policies and human rights practices.

President Hu Jintao opened the relay at an elaborate ceremony in Tiananmen Square in the heart of the capital, underlining the importance China places on the Olympics and its hopes to display a confident, strong nation to the world when the Games open Aug. 8.

The ceremony 130 days before the start of the Olympics was broadcast on state television, and comes a week after the lighting ceremony for the Olympic torch in Greece was marred by protests.

"I declare the torch relay of the Beijing 2008 Olympic Games begun," Hu said after handing the flame off to China's Olympic and world champion hurdler, Liu Xiang. Liu jogged off the square as confetti flew, Chinese and Olympic flags waved and traditional drums pounded.

After a one-day stop in Beijing, the flame goes tomorrow to Almaty, Kazakhstan, the start of a monthlong 20-country, 85,100-mile global journey.

The grandiose relay is the longest in Olympic history and has the most torchbearers — a sign of the vast attention lavished on the Games by Beijing, which hopes to use it to showcase China's rising economic and political power.

Instead, however, it has provided a stage for human rights activists who have been criticizing China over a range of issues including its handling of Muslims in the far west of the country, its control over Tibet and its relationship with Sudan.

Tibetan and rights groups have said they will stage protests along the torch route, which includes stops in London, Paris and San Francisco over the next 10 days.

The relay has especially focused attention on recent unrest in Tibet, the worst in the Chinese-controlled region since 1989.

The flame arrived from Greece early yesterday aboard a chartered Air China plane, greeted at Beijing airport by hundreds of flag-waving schoolchildren.

Amid tight security, police and paramilitary officers were stationed on overpasses, bridges and entry ramps along the flame's route into the city. Police closed Tiananmen Square to vehicles, and pedestrians and bicyclists were kept one block away. Authorities also closed off Chang'an Boulevard, the capital's main thoroughfare.

About 5,000 people, including 220 foreign journalists, were on hand for the ceremony. Bright red seats faced north to where a huge portrait of Mao Zedong overlooks the square. Martial artists and dancers in minority costumes, including those of Tibetans, cavorted on a huge red carpet covering much of the north end of the vast square in the heart of the capital.

The ceremony mixed bright colors and a modern look with military music and imagery from China's imperial past. Top Communist Party officials spoke of global understanding and respect, but also sprinkled their address with familiar political catch phrases.

"Now the Olympic flame has brought the noble Olympic spirit to China. The burning Olympic flame will spread the message of peace and friendship and unite all people under one world, one dream," Liu Qi said, invoking the Beijing Games' official slogan.

State television's live broadcast of the ceremony was delayed by about one minute, apparently to ensure the feed could be cut if there were any disruptions.

Last week, the China Central Television broadcast cut away from the flame lighting ceremony in Greece when protesters ran behind chief Beijing organizer Liu Qi as he gave a speech. It showed stock footage of the ceremony site instead.

Hein Verbruggen, the only foreign IOC official to address the ceremony, made no mention of potential problems.

"All along the relay route people will be touched by the Olympic Games and what it means," said Verbruggen, who heads the IOC commission monitoring Beijing Games preparations.