 Bolivian television showed two tanks and a number of men in military uniforms outside the building. But troops and armored vehicles later began to pull back. Supporters of Arce flooded into the plaza outside soon afterward. I'm Hayabin Juwan. Chinese space officials welcoming researchers from across the world to apply to study rock samples a country's lunar probe brought back to Earth. But they add there are some limits to cooperation specifically with the U.S.