A search was under way for two missing crew members after two Royal Air Force Tornado fighter jets crashed while on a training exercise in Scotland, Britain's Ministry of Defence said.
Two other air crew were rescued following the incident which occurred over the Moray Firth estuary off the Scottish east coast, but there was no information about their condition.
"The circumstances remain uncertain but clearly this is a very serious incident," said Group Captain Ian Gale, Station Commander at RAF Lossiemouth where the jets were based.
"I can confirm that two individuals have been recovered and two remain unaccounted for. Rescue operations are continuing and I would like to record my gratitude for the ongoing efforts of all those involved."
Lifeboats are searching the area for the missing crew from the Tornado GR4 aircraft, a heavily armed attack jet which has been used by the RAF in a number of recent military operations including Afghanistan and Libya.
The incident is the latest crash involving RAF jets in Scotland where they routinely undergo training missions.
In January 2011, the two-man crew in a Tornado GR4 from RAF Lossiemouth ejected before their plane crashed into the sea off northwest Scotland.
Two crewmen were killed in 2009 when their Tornado F3 when crashed in Argyll, near Loch Lomond, during a routine training flight.
"I am confident that the Tornado aircraft on this station are operated as safely as they possibly can be. However, today's incident is a stark reminder that the military operations and training we conduct are not without risk," Gale said.
"What happened today is under investigation and more details will be released by the Royal Air Force in due course."
