Two RAF personnel have been killed in a helicopter crash in Kabul, Afghanistan, the Ministry of Defence (MoD) has said.
A spokesman said an investigation was under way but confirmed it was "an accident and not the result of insurgent activity".
The Puma Mk2 helicopter crashed as it was landing at Nato's Resolute Support mission headquarters on Sunday.
The families of the victims have been informed and asked for a period of grace before their names are released.
Two
British fighters with so-called Islamic State were killed by an RAF
drone strike in Syria in an "act of self-defence", David Cameron has
said.
Cardiff-born Reyaad Khan was targeted in Raqqa on 21 August
and died alongside Ruhul Amin, from Aberdeen, and another fighter, the
PM told MPs.
Khan, 21, had been plotting "barbaric" attacks on UK soil, he said.
The action was lawful and necessary, Mr Cameron said, despite MPs previously ruling out UK military action in Syria.
In a statement to the Commons, Mr Cameron said: "My first duty as prime minister is to keep the British people safe.
"There was a terrorist directing murder on our streets and no other means to stop him.
"This government does not for one moment take these decisions lightly.
"But
I am not prepared to stand here in the aftermath of a terrorist attack
on our streets and have to explain to the House why I did not take the
chance to prevent it when I could have done."
Analysis
By BBC defence correspondent Jonathan Beale
Unmanned
Reaper drones joined RAF Tornado jets in conducting surveillance and
air strikes soon after Parliament authorised military action against the
group calling itself Islamic State last September.
The vote
confined that military action to Iraq, but at the time the prime
minister told MPs he "reserved the right" to act elsewhere "if there
were a critical British national interest at stake".
The
government will argue the air strike on Reyaad Khan was such a case. But
carrying out an RAF airstrike in Syria will still be controversial;
even more so because a British citizen was targeted.
Though
government officials insist that he posed a direct threat to the UK and
was on a legitimate "target list", there'll be plenty of questions. What
was the intelligence on which the decision was based? Who's target list
was he on?
There are reports the CIA has compiled a list of
high-value targets. There will inevitably be some suspicion around the
secrecy - the MOD has never publically stated how many Reapers the RAF
are operating or where they're based.
The fact that RAF Reapers
have been flying over Syria is not in itself a surprise. Defence
Secretary Michael Fallon told MPs last October they would be conducting
surveillance missions.
But in a written statement he also stated:
"Reapers are not authorised to use weapons in Syria; that would require
further permission."
RAF Typhoon fighter jets were
scrambled after two Russian military aircraft were seen flying towards
UK airspace, the Ministry of Defence (MoD) has said.
The British jets were launched from RAF Lossiemouth after the Russian planes were spotted north of Scotland.
An MoD spokesman said: "At no time did the Russian military aircraft cross into UK sovereign airspace."
The Russian bombers were not deemed to be a threat, he added.
The aircraft were identified as Russian "Bear" strategic bombers.
It is the latest of several similar incidents involving Russian military aircraft flying close to UK airspace.
'Flexing military might'
BBC
defence correspondent Jonathan Beale says the RAF is "pretty used to
this now" and seems to be intercepting Russian planes "about once a
month".
He said: "There has been a dramatic increase in Russian
encroachments - this year there have been three times as many [RAF]
intercepts as previous years.
"The worry is when these Russian
bombers come, there's no signal - they don't have their transponder,
they are not 'squawking' - so in other words, only military radar pick
them up."
With the Russians investing heavily in their military, he said it was "another example of Russia flexing its military might".
Warfare exercise
Russian officials have consistently denied any wrongdoing and said their planes have been complying with international rules.
Tensions
between Nato countries and Russia have risen in recent months over
Moscow's role in the conflict in Ukraine and its annexation of Crimea.
In the North Sea, off the coast of Norway, Nato has been conducting its largest ever anti-submarine warfare exercise.
It is seen as a response to the growing threat from Russian submarines which have stepped up their own patrols in the area.
RAF jets were scrambled on Wednesday
after two Russian military aircraft were seen off the Cornwall coast,
the Ministry of Defence has said.
The Russian Bear bombers did not enter sovereign airspace, it said.
On
the same day, Defence Secretary Michael Fallon warned that Russia's
President Putin posed a "real and present danger" to three Baltic
states.
Prime Minister David Cameron said the Russian action should not be dignified with "too much of a response".
He
added: "I think what this episode demonstrates is that we do have the
fast jets, the pilots, the systems in place to protect the UK.
"I suspect the Russians were trying to make some sort of a point."
BBC
political correspondent Ross Hawkins said the appearance of Russian
aircraft near the UK coast was a show of strength from the Russians, and
such incidents were carried out with political intent because they
would be reported on.
Our correspondent said it was part of a
trend which had seen Russian aircraft flying close to UK airspace and
there had also been concern about similar incidents in Europe.
It comes amid increased concerns over Russian involvement in the
conflict in Ukraine and suggestions of Russian President Vladimir
Putin's potential future interference in Latvia, Lithuania and Estonia.
A ceasefire deal between government and pro-Russian rebel separatists in Ukraine was reached a week ago.
But battles around the strategic town of Debaltseve have seen the withdrawal of Ukrainian troops, while there was shelling in several places in eastern Ukraine, including the region's biggest city, Donetsk, on Thursday.
'New' Cold War
Russia
has denied helping the separatists, but it has been accused repeatedly
of sending weapons and troops and using propaganda to inflame tensions.
And
Russia's UN ambassador Vitaly Churkin has labelled Ukraine's call for
the deployment of UN peacekeepers in eastern Ukraine as a destructive
move.
Mr Cameron has said rebels in eastern Ukraine are using
Russian military hardware, and that Mr Putin must understand there would
be "economic and financial consequences for many years to come" if he
did not change his behaviour.
Speaking to journalists from the Times and Daily Telegraph
on Wednesday, Mr Fallon said the increase in Russian defence spending
was "clearly worrying" and that he was also "worried about Putin".
"They
are modernising their conventional forces, they are modernising their
nuclear forces and they are testing Nato, so we need to respond."
Mr Fallon also said the prospect of a new Cold War was "warming up".
"You
have tanks and armour rolling across the Ukrainian border and you have
an Estonian border guard who has been captured and not yet still
returned."
Previous incidents
He also said Russia was likely to use covert tactics such as those he
said it had used to annex Crimea and during the current Ukraine
conflict.
Mr Putin had also flown two other bombers "down the English Channel two weeks ago", Mr Fallon added.
"We had to scramble jets very quickly to see them off.
"It's the first time since the height of the Cold War, it's the first time that's happened."
Analysis
Jonathan Marcus, BBC defence and diplomatic correspondent
The
comments from Defence Secretary Michael Fallon are an indication of a
fundamental shift in the Nato perception of the crisis in Ukraine.
Nato
governments clearly believe that what began as a localised Ukraine
problem that strained ties with Moscow has now become a Russia problem,
and a Russia problem that is likely to persist for some time.
Ukraine is thus seen as a manifestation of a much broader policy shift on the part of the Russian President Vladimir Putin.
Mr
Fallon's belief that there is indeed a potential threat to Nato
territory - in particular the Baltic Republics - is widely shared; hence
Nato's desire to underline in the most emphatic terms that its security
guarantees to its members will be honoured in full. Russian
Foreign Ministry spokesman Alexander Lukashevich said Mr Fallon's
comments went "beyond diplomatic ethics" and used "unacceptable
terminology".
He also said Russia would "find a way to respond".
According
to the Department for Transport, there was no record of disruption to
civil aviation as a result of the bombers' presence on Wednesday.
The
MoD said: "RAF Quick Reaction Alert Typhoon fighter aircraft were
launched [on Wednesday] after Russian aircraft were identified flying
close to UK airspace.
"The Russian planes were escorted by the
RAF until they were out of the UK area of interest. At no time did the
Russian military aircraft cross into UK sovereign airspace."
A
similar incident occurred in January, when the UK Foreign Office said
two Russian Tu-95 Bear H bombers flying near UK airspace had caused
"disruption to civil aviation" and were also escorted by RAF jets while
near UK airspace.
Deputy Prime Minister Nick Clegg said the latest
incident "shows that we are of course living in a time of heightened
tension with Russia... and we should remain vigilant at all times".
