BEIJING  President Hu Jintao of China waved the Olympic torch at a ceremony in Tiananmen Square on Monday, smiling as balloons, streamers and confetti filled a mostly blue sky.

Then came the uncertain part. Mr. Hu sent the torch on a 130-day journey that includes places where protests and controversy most likely await. One eventual stop on what Beijing is calling a “Journey of Harmony” will be Lhasa, the Tibetan capital still simmering from violent antigovernment protests.

“I now declare the launch of the torch relay for the 2008 Beijing Olympic Games,” Mr. Hu said in his only line in a tightly scripted celebration, broadcast across China on state television. Mr. Hu, the Communist Party leader, then handed the torch to China’s star hurdler, Liu Xiang, who raced off to culminate the ceremony.

Earlier Monday morning, the Olympic flame arrived in Beijing from Athens on an Air China jet decorated with golden flames. This week, the Olympic flame is being split into two torches, according to Jeff Ruffalo, a public relations adviser to the Beijing Olympics. One will be flown Tuesday to Almaty, Kazakhstan, to begin an international relay covering five continents and including a stop in San Francisco.