Chinese scientists said the country’s massive Sky Eye telescope may have picked up signals of an alien civilization, Business Insider reported. But there is still much due diligence left to be done, and a scientist involved in the study is now pushing back.

According to a report published in the state-backed Science and Technology Daily on Tuesday, Beijing Normal University researchers discovered “several cases of possible technological traces and extraterrestrial civilizations from outside the earth.” The researchers utilized the only giant single-dish radio telescope left in the world, China’s 500-meter Aperture Spherical Radio Telescope (FAST), to make the discovery. Cosmologist Zhang Tongjie told Science and Technology Daily that the telescope had located “several narrow-band electromagnetic signals different from the past.”

According to the cosmologist, the signals could simply be radio interference.

“The possibility that the suspicious signal is some kind of radio interference is also very high, and it needs to be further confirmed and ruled out,” she said. “This may be a long process.”

As reported by Bloomberg, the initial Science and Technology Daily report was later removed from the website, which is run by China’s science and technology ministry. It is still unclear why the report was removed, as the news was later picked up by other state-run Chinese sources.

In an interview with Futurism, SETI researcher at the University of California, Berkeley, Dan Werthimer said that the signals are categorically terrestrial and not from an alien civilization. Werthimer coauthored a preprint about the findings.

“The signals that we found so far are all [radio frequency] interference, they’re not from extraterrestrials, they’re from terrestrials,” he said.

“The problem is that when you look for these very weak signals from a distant civilization, you get overwhelmed by the the pollution, the radio pollution on Earth,” Werthimer said. “All this television and cell phones and satellites now are getting worse and worse and it’s hard to figure out what’s interference and what might be from a distant civilization.”

Since Sept. 2020, the $171 million observatory has been largely dedicated to searching for extraterrestrial life. Researches have since discovered two sets of signals from 2019 and one from 2022 while processing data this year.