A man hopped over a security barrier in the British Museum on Monday and tied surgical masks to the faces of two Chinese terracotta warriors in a protest against China’s pollution problems.

The environmental protester stepped over a knee-high barrier to attach masks emblazoned with "CO2," the chemical notation for carbon dioxide. The movement near the statue triggered a silent alarm at the museum’s security center, but not before the masks were put on two of the warriors.

Security guards stopped the man and escorted him away after alarms sounded, museum spokeswoman Hannah Boulton said. The man was not arrested and the statues were not damaged, she said.

Source: Cnn