Residents in China were baffled by an unidentified flying object streaking through the sky, sparking speculation it could be a secret missile test.
Videos posted on social media showed a mysterious moving white trail in the early hours of Sunday morning.
It prompted onlookers to speculate about 'alien activity' or a military test after the phenomenon was seen in four different regions in China.
The sighting came three days before China launched a space rocket at sea for the first time .
China's Liaoning Maritime Affairs Bureau issued a warning of a military drill in the Bohai sea, the innermost gulf of the Yellow Sea, on the same day as the Sunday sighting.
It stated no ships were allowed to enter the Bohai Sea and Bohai Strait between 2.30am to noon.
According to local media, the sighting is believed to be from an underwater missile equipped with a hypersonic warhead.
Military experts suggested it could be JL-2B orJL-3 missile, an intercontinental-range submarine-launched ballistic missile.
The JL-3 ballistic missiles could carry six to ten warheads and travel up to 12,800 km, it is reported.
The range is sufficient to reach all areas of Europe, India and Russia.
There are also reports the JL-3 missiles will be carried by China's Type 096 ballistic missile submarines but it has not been confirmed by any authorities.
Zhao Haibing, a researcher at Purple Mountain Observatory, told Huanqiu that the mysterious object is 'unlikely to be a natural glowing object'.
He added that the object could have been launched from the ground.
The Chinese authorities have not commented on the incident.
However, China did confirm the the sea-based Long March 11 rocket launch on Wednesday.
It carried two experiment and five commercial satellites, launched from a mobile pad on a ship in the Yellow Sea off the coast of Shandong province.
China is currently one of the six countries that are equipped with nuclear-powered submarines.