China's pyramids in danger of collapsing

Tombs almost 1,000 years old in western China -- known as the "pyramids of the east" -- are in danger of collapse due to natural erosion and man-made damage, Chinese state television said on Wednesday.

The Western Xia Tombs, in the poor, remote region of Ningxia, house the remains of kings of an empire that once stretched to the borders of Tibet and developed its own complex written script based, like Chinese, on pictographs.

Reuters: China's "pyramids" in danger of collapsing -report

But why do they have "pyramids" in quotes? Do Reuters think that Egypt has the only pyramids?