Beijing has earmarked three areas for public protests during the Olympic Games, a senior security official said Wednesday.

"We have designated areas in three Beijing parks for demonstrations during the Olympics," Liu Shaowu, director of security department of the Beijing Olympic organizing committee (BOCOG), said.

"The country's law grants people the right to hold peaceful demonstrations," he said. But such people have to get the authorities' permission before holding a protest.

"To maintain smooth traffic flow, a pleasant environment and good social order during the Games, we urge protestors to demonstrate only in the designated areas," he said. "This has been the practice during earlier Games too."

The three designated parks in Fengtai, Haidian and Chaoyang districts are away from the Games venues and sites because the Olympic Charter prohibits demonstrations or "political, religious or racial propaganda" there.

About 110,000 policemen, volunteers and other personnel will be on duty to ensure a safe Olympics, Liu said.

As part of the security measures, fences have been built and security checkpoints set up around the Olympic Village, Games venues and the BOCOG headquarters, and monitoring and alarm systems installed there.

Armed police with trained dogs are on round-the-clock patrol at Beijing airport and the four major railway stations. Long-distance bus depots and subways are on high alert too.

Liu said earlier host cities had adopted similar security measures and that the BOCOG will try to balance safety and festivity.

This is the first time China is holding such a big sports event, he said. "And the huge number of people coming to China can make terrorists launch an attack."

After Monday's bus explosions in Kunming, Beijing has intensified security checks at bus stations and in public transport, he said.

Painstaking efforts have been made to strengthen community patrols, crack down on criminal activities and tighten management over dangerous goods, Liu said.

"We are confident we can create a safe and joyous atmosphere for the Games."

Agencies contributed to the story