Describing it as the “most promising lead” yet: a month into the hunt for missing Malaysia Airlines flight MH370, search crews have detected two signals consistent with those from ‘black box’ flight recorders.

A US Navy “towed pinger locator” connected to Australia’s Ocean Shield ship picked up the beacons in an area around 1,680 kilometres northwest of the Australian city of Perth. This zone had already been determined as the most likely place the jetliner would have gone down.

But US Navy Captain Mark Matthews has asked people not to get their hopes up.

“We’d like to be able to tell the families that we found the location, but until we can reconfirm, you know, we should not be too optimistic,” he said. “We should be very measured, because the worst thing we want to do is put the families through the emotional turmoil of possible, but maybe false, detections.”

The exact position of the signals will have to be fixed before trying to locate wreckage on the seabed.

But the flight recorder’s batteries are due to run out, meaning there would no longer be a signal.

Malaysia’s defence minister and acting transport minister Hishamuddin Hussein has urged the public to continue to support the search efforts.

“The new developments over the last few hours has been the most promising lead we’ve had. I urge all Malaysians and the international community to unite in their prayers and not give up hope,” he said.

It seems people are heeding his message. On Sunday more than 3,000 people gathered to pray for those on the missing jet, in a ceremony hosted by the Malaysian Chinese Association.