British diplomat summoned by Russia over 'missile' reports
Russia summoned Britain's defence attache in Moscow to explain reports that RAF pilots had been authorised to shoot down Russian aircraft in the Middle East, the Foreign Office says.
Newspapers said RAF Tornados in Iraq had been fitted with heat-seeking missiles designed for aerial combat.
But the Ministry of Defence said there was "absolutely no truth" in this.
The Foreign Office said concern about Russian military action in Syria had been reiterated by the attache.
Prime Minister David Cameron has previously said Russian military intervention in Syria is helping only to support "the butcher", President Bashar al-Assad.
He has also expressed concerns that Russian forces are not discriminating between air strikes on Islamic State (IS) militants and others fighting the Syrian president.
The RAF has been carrying out air strikes against IS militants in Iraq since the action was approved by MPs in 2014, but UK military intervention in Syria has not been backed in Parliament.
By Jonathan Marcus, defence and diplomatic correspondent, BBC News
This curious footnote to the air campaign being waged over Iraq and Syria illustrates the potential for misunderstanding now that Russia is conducting major independent operations of its own.
RAF Tornados based in Cyprus are carrying out air strikes only in Iraq, though potentially could be flying over Syria on intelligence gathering missions as well.
Either way, en route to or from Iraq, they could come into close proximity with Russian warplanes.
However, the Ministry of Defence in London has denied any suggestion that they are being armed with air-to-air missiles so as to defend themselves in any encounter.
The Russian government called in the British air attache in Moscow after reading erroneous reports in the British press suggesting air-to-air missiles were being fitted.
A Foreign Office spokesman said the defence attache met Russian ministry of defence officials on Sunday.
"The Russian government sought clarification over inaccurate newspaper reports concerning RAF rules of engagement in Iraq," the Foreign Office spokesman said.
"The defence attache reiterated the British government's concerns about Russia's military operation in Syria, including targeting legitimate opposition groups, using unguided weaponry and leading to large numbers of civilian deaths."
Russian President Vladimir Putin has defended the military operations in Syria, saying the aim is to "stabilise the legitimate authority" of Mr al-Assad.
He denied that Russian air strikes were hitting moderate opposition groups rather than IS militants.
Mr Putin told Russian state TV that Moscow also wanted to "create conditions for a political compromise" in Syria.
In 2013, British MPs voted against action in Syria, amid claims - denied by President Assad - that he was using chemical weapons against his own people.
Now the government wants to extend its bombing campaign against IS militants from Iraq into Syria, but says it will only do so with Parliamentary approval.
Earlier this month Defence Secretary Michael Fallon said the government was working hard to build a consensus to get Parliamentary support.