At least three people died and 14 were injured as three buses exploded this morning in the southwestern city of Kunming.

Even though China has dramatically tightened security throughout the country ahead of the Olympis, the blasts were deliberate ”sabotage”, according to the state news agency Xinhua.

Shortly after the explosions that took place in the morning rush hour, the police introduced roadside checks in Kunming, the capital of Yunnan province, to try to track down the person or persons responsible.

Xinhua said that two persons were killed at the scene and one on the way to hospital.

Reuters reports of a Yunnan government official calling from Kunming saying that there had only been two explosions. The official declined further comments.