The loss of EgyptAir flight MS804 has entered that terrible place where an airliner has clearly crashed, but nothing has been found by way of wreckage and very little is known about the circumstances.

One of the most responsible and informative live blogs on the situation is being run by The Guardian.

What can be said? It is certain that the flight from Paris to Cairo has crashed, and in the general area of the Mediterranean where it had just entered Egypt’s air space shortly before its intended arrival.

It isn’t unreasonable to fear that it was brought down by a terrorist act, but there are other possibilities.

There are unconfirmed reports of a fireball being sighted from a Greek island, and of a distress call being heard just before it disappeared off ATC radar, and of a locator signal that could have been deployed automatically on impact being detected some hours after the A320 with 66 people on board was due to have landed.

EgyptAir initially said that a locator beacon had been heard some hours after contact with the A320 was lost, but this has been withdrawn. Egypt said wreckage from the flight had been located near the Greek island of Karpathos, but a few hours later this was said to be a mistake.

Almost every material statement about wreckage, radar swerves and other colourful reports have now been repudiated or remain under severe doubt. There has been no unambiguous finding of bodies or wreckage from the EgyptAir jet.

There is nothing unusual about its being at 37,000 feet at the moment radar contact was lost. There is nothing unusual about there being three security people on board.

Beyond that, nothing is known, and some of what has been reported may not prove to have been accurate.