The debris is believed to be from a Chinese booster rocket that returned to Earth on Saturday.
According to a Malaysian news outlet, a five-metre ring of metal was found in Indonesia. The metal appeared to be the same size as the Chinese rocket's core stage, according to an astronomer.
He said it looked like the end cap of a propellant tank. I think it is from the right kind of rocket and it is in the right place at the right time.
The second module was carried by the Long March 5B rocket. China said it would keep a close eye on the debris and that it posed no risk.
The core stage of the rocket should not be allowed to return to Earth.
The administrator of Nasa, Bill Nelson, chided China for not sharing information on the rocket's descent, saying it was irresponsible and risky. All spacefaring nations should follow established best practices, and do their part to share this type of information in advance to allow reliable predictions of potential debris impact risk, especially for heavy-lift vehicles, which carry a significant risk of loss of life and property.
Two years ago, fragments of a Chinese Long March 5B caused damage to several buildings. There were no injuries that required hospitalization.
Two families were evacuated from their homes in Sarawak, Malaysia due to concerns about radioactivity after a piece of debris was found nearby.
The piece of metal was half a meter in the air. The incident was being investigated by the Malaysian space agency and atomic energy licensing board.
It was difficult to tell from the quality of the photo whether the image was of debris from the rocket, but he was confident that several parts landed near the Indonesia and Malaysian border.
One day after people in Sarawak posted images of debris lighting up the night sky, the discovery was made. Aizul Sidek said that they thought it was a shooting star.
A resident told local media that at about 12.40am he heard a loud noise and felt an earthquake.
Most spacefaring nations designed rockets to prevent re-entries. He said that there was no international law requiring this, but that avoiding the risk became an imperative after the fall of the Skylab space station.
Three of the biggest re-entries of the space age were Chinese rockets.
The fact that they are different from what other countries are doing shows you that they are.
There have been no casualties from rockets in the 60 years since they were first used. We would like to keep it that way. China is becoming one of the leading space powers and so we need to find a way to bring them into the family of space nations.