Britain is doubling the number of Chinooks within range of Baghdad and putting Royal Marines on standby as tensions between Iran and western powers continue to grow.

As many as five of the heavy-lift helicopters are expected to be deployed from RAF Odiham in Hampshire within a number of days to the Middle East following an Iranian attack on Iraqi Al Asad and Erbil air bases - which host US and Coalition forces.

Four Chinooks - troop and supply transporters armed with machine guns - are currently stationed in Arbil, northern Iraq, but the precise destination of the five extra aircraft has not been disclosed for security reasons, the Times reported.

And Britain's elite Royal Marines have been put on 12-hour standby to help evacuate British troops and civilians in the case of war in Iraq - as Foreign Secretary Dominic Raab today calls for 'urgent de-escalation' in the region, saying a war would 'only benefit Daesh and other terrorist groups'.

As many as five of the heavy-lift Chinook helicopters are expected to be deployed from RAF Odiham in Hampshire within a number of days to the Middle East (file photo: British Royal Marines exit a Chinook in Afghanistan, 2002)

A man holds a picture of late Iranian Major-General Qassem Soleimani in the street in Tehran today after Iran launched missiles at US-led forces in Iraq

Warships HMS Defender and HMS Montrose are currently in the Gulf to escort British shipping, the Mirror reports.

There are currently 1,400 British military and civilian personnel in Iraq to help the battle against Isis, and it is thought the additional helicopters - each capable of carrying up to 55 troops or ten tonnes of cargo - could be used to take Britons out of the country.

The move comes as part of the Ministry of Defence's contingency planning in case of revenge attacks following the assassination of Iran's Revolutionary Guard General Qassem Soleimani.

Foreign Secretary Dominic Raab is calling for 'urgent de-escalation' following an attack on Iraqi military bases

Defence Secretary Ben Wallace said British helicopters and warships are 'on standby to assist if the need arises', adding that all non-essential military personnel had been taken out of Baghdad's green zone due to security concerns.

The announcement comes after Iran fired 22 missiles at US bases in Iraq in an operation called 'Martyr Soleimani'.

The UK's Ministry of Defence confirmed that no British military personnel were injured in the barrage.

Today Foreign Secretary Dominic Raab is called for de-escalation following the attack on Iraqi military bases.

He said: 'We condemn this attack on Iraqi military bases hosting Coalition - including British - forces.

'We are concerned by reports of casualties and use of ballistic missiles.

'We urge Iran not to repeat these reckless and dangerous attacks, and instead to pursue urgent de-escalation.

'A war in the Middle East would only benefit Daesh and other terrorist groups.'

And the European Union said today it 'will spare no efforts' in its attempts to keep alive an international deal preventing Iran from developing atomic weapons.

EU Commission President Ursula von der Leyen said her foreign affairs chief Josep Borrell will continue to work 'in the midterm' to reach out to all participants in the global deal in the hopes that the 2015 nuclear agreement can still be saved despite a rollback on commitments from Tehran.

Residents look at a crater caused by a missile launched by Iran on US-led coalition forces on the outskirts of Duhok, Iraq, January 8

Royal Marines were put on 12-hour standby to assist in evacuating British troops and civilians in the case of war in Iraq (file image)

Iraqi security forces clear away pieces of shrapnel from the Ain al-Asad airbase after it was struck by ballistic missiles fired by Iran as part of operation 'Martyr Soleimani'

Von der Leyen also reiterated the need to de-escalate the tension in the region, especially after Iran's missile attack on two American bases in response to a US strike that killed its top general.

Speaking alongside von der Leyen, Borrell urged all parties involved in the growing tensions to eschew more military action.

'The latest rocket attack on airbases in Iraq used by U.S. and coalition forces, among them European, is yet another example of escalation and increased confrontation. It is in no one's interest to turn up the spiral of violence even further,' he said.

Borrell has invited Iran Foreign Minister Javad Zarif to Brussels for talks. The EU foreign ministers have organized a special meeting on Friday to discuss the ongoing crisis.

After its top general was assassinated in the U.S. drone attack, Iran announced over the weekend that it would no longer respect limits set on how many centrifuges it can use to enrich uranium.

Zarif said the move was a 'remedial step' taken within the framework of the nuclear deal and he said it could be reversed.