Chinese researchers have detected a “seafloor event” near the waters between Malaysia and Vietnam, an area suspected to be linked with the missing Malaysian jetliner that disappeared nearly a week ago.

The event occurred at about 2:55 a.m. local time on Saturday, about one and a half hours after the plane’s last definitive sighting on civilian radar, state-run Xinhua news agency reported, suggesting a tremor of a kind on the floor bed of the sea.

The area, 116 km northeast from where the last contact with the Boeing plane was recorded, used to be a non-seismic region, according to a research group on seismology and physics of the earth’s interior under the University of Science and Technology of China.

The seafloor event could have been caused by the plane possibly plunging into the sea, the research group said.

The plane carrying 239 passengers and crew went missing on last Friday. There was no clue so far about its whereabouts despite intense search involving planes and ships from several countries.