At the start of their training, some of the dogs did not perform too well, Tang said.

Members of the police staff from China's 20 provinces walk their dogs inside an Olympic venue in Beijing, July 2, 2008. A total of 204 sniffer dogs and their masters will be responsible for security in Beijing during the Olympic and Paralympic Games from August. [Asianewsphoto] More Photos

Some of them scratched at the bombs when they found them - something that is strictly forbidden as it may cause an explosion - which was unusual, but we put it down to them being in a strange environment, he said.

"But after a month's training, they are all working superbly. In their last test, they all got straight As," he said.

Tang said all the dogs have been vaccinated against disease, and the facility has quarantine rooms for any that are suspected of being sick.

"Fortunately, though, none of them has been ill," he said.

An Ran, Hurley's handler, said that while all the selected dogs are impressive, there is no doubt which one is the best.

"My Hurley has been sniffing out explosives since he was 8 months old," he said.

"He's so good, he is always chosen to do the most important jobs whenever State leaders like President Hu Jintao and Premier Wen Jiabao visit my province."

The 30-year-old officer from Heilongjiang province, who recently got married, said Hurley is not just a colleague, he is more like a son.

"I've had him since he was just 3 months old, and I've spent every New Year's Eve with him since," An said.

Both he and his dog are sleeping and eating well in Beijing, he said.

"He has three two-hour classes every day, two in the morning and one in the evening," he said.

"He also has two meals a day, with a daily budget of 20 yuan. Usually, he gets only dog food."

At the end of the demonstration, An called, "Foot up!" and Hurley lifted his left paw, as if he was waving goodbye.

An then called, "Another!" and Hurley swiftly changed paws and "waved" with his right.

"See how clever and nice he is?" An said.

"But if I'm not with him, even my wife cannot touch him. Hurley will even refuse to eat if I am away from him for more than three days."