The Foreign Office has been told to prepare for “crisis mode” as weapons were flown from Britain to Ukraine to defend it from a Russian invasion.
It comes as the White House reviews evidence from US intelligence suggesting Russia is planning to attempt to take Ukraine’s capital, Kyiv, and overthrow the government.
Joe Biden is now thought to be weighing up new options for dealing with the crisis, including providing more arms to Ukraine.
Jen Psaki, White House spokesman, said: “We believe we’re now at a stage where Russia could at any point launch an attack on Ukraine.”
A White House official warned that Russian troops being sent for exercises in Belarus could be used to attack Ukraine.
Additional arms would include more ammunition, mortars, Javelin anti-tank missiles, and anti-aircraft missile systems, which would likely come from Nato allies, sources told US media.
Ben Wallace, the Defence Secretary, announced on Monday that the UK had started supplying Ukraine with Next Generation Light Anti-tank Weapons (NLAW) to help it defend itself from a potential invasion.
Officials at the Foreign Office have been told to be ready to move into “crisis mode” at very short notice, highlighting the increased concern that Russia’s aggression toward Ukraine could lead to an invasion.
Staff at the department were said to have been informed of the request this week. Triggering it would mean officials and diplomats are redeployed to work on Russia and Ukraine policy and to prioritise the UK response to any further spike in tensions, including deterrence and sanctions.
According to Bloomberg, staff in the department were told: “This is critical work in shaping and securing our European neighbourhood.” Some staff are already being shifted to work on contingency planning and strategic communications, the person said.
The Foreign, Commonwealth & Development Office said: “The emerging situation in and around Ukraine is a top priority for the FCDO and, as everyone would expect, we have robust contingency plans in place to respond to any developments.”
The spokesman added: “The Foreign Secretary is clear that Russia’s aggression towards Ukraine is unacceptable and unprovoked, and that any incursion would be met with massive consequences and severe costs”.
Speculation grew on Tuesday that British C-17 aircrafts carrying weapons to Ukraine had taken detours in order to avoid flying over German airspace.
The military flights to Ukraine over the weekend, tracked by commercial radar, showed the C-17s bypassing German airspace, opting instead for a longer route over Denmark and Poland.
The route, which saw the aircraft fly over Denmark and Poland rather than take a more direct path, has led to speculation that Germany may have reservations about the military support to Ukraine.
An RAF source told The Telegraph that Ben Wallace has been on a variety of visits over Scandinavia and north eastern Europe and the flight path reflects these recent visits. They said Mr Wallace has yet to meet his new counterpart in Germany and that waiting for permission to fly over Germany could have held up the flight.
They stressed that how the C-17 gets to northern Europe was “irrelevant”, adding that “the quickest way to get flight clearance was to go through the route we went”.
“We didn’t apply for flight clearance to go through Germany because it would take too long.”
An MoD spokesman said: “Germany has not denied access to its airspace as the UK did not submit a request, there has been no dispute between the UK and Germany on this issue.”
British diplomatic sources in Berlin said the route was chosen for operational reasons, including a standing policy of avoiding flying weaponry over heavily populated areas.
Germany ruled out export of weapons to Ukraine
While Germany has publicly pledged its support for Ukraine against any Russian aggression, it has ruled out allowing its own defence sector to export weapons to Kiev over fears it could “inflame” the situation.
Angela Merkel’s government twice intervened to veto the delivery of weapons Ukraine had already paid for, including a US shipment of rifles and anti-drone systems from Lithuania.
Annalena Baerbock, the German foreign minister, insisted her country would stick to its ban on German weapons exports on a visit to Kiev this week.
“Our stance is not only well known, but historically well founded,” Ms Baerbock said.
But she has not commented on whether the new German government plans to continue Mrs Merkel’s policy of obstructing its allies from arming Ukraine.
British anti-tank firepower beefs up Ukraine’s defences
In service with the UK, Finland, Sweden and Luxembourg, the Next Generation Light Anti-tank Weapon (NLAW) is designed to be used by non-specialist troops after minimal training.
The missile is best used against tanks, where it detonates just above the top of the vehicle, but can be fired directly at vehicles, bunkers and buildings.
The weapon is not guided but instead tracks the speed and direction of the target for a few seconds prior to launch to predict where the tank will be.
The soldier firing the NLAW will set the distance to the tank being targeted. Magnetic and optical sensors on the missile then confirm that other vehicles such as previously destroyed tanks or civilian cars on the flight path are not the intended target, in which case the weapon will not function.
Only when the sensor data on the missile confirm it has reached the intended target will the warhead detonate, at about 1m above the target.
© Provided by The Telegraph The Next generation Light Anti-tank Weapon (NLAW) is designed to be used by non-specialist troops after minimal training
The warhead is angled down at 90 degrees to give it the best chance of penetrating the top of the tank – often the least protected part of the vehicle.
Recognising the potential for warfare in urban areas, the weapon was designed to be fired from within buildings.
Older anti-tank weapons produce a huge backblast on launch which can injure or even kill soldiers firing it if they are in enclosed spaces.
By contrast, the NLAW fires a rocket booster to move the missile clear of the launch tube first, before the main propellant charge ignites after a few metres of flight. The missile then races towards the target at around 450mph.
The weapon will further bolster the Ukrainian military. It is in a much better state than in 2014 when Russia annexed its Crimean peninsula without a shot being fired, but still has significant gaps in its defences.
Moscow outstrips its abilities on almost every front, particularly when it comes to the air force and navy.
Ukraine’s ground forces may as well be well-trained and equipped to fight off a limited land invasion but Russia’s capabilities at sea and in the air would pin down Ukraine’s ground troops wherever they are.
But after receiving billions of pounds of military aid from the West, the Ukrainian army is fully equipped with drones, artillery radars and other types of non-lethal weapons.
Ukraine last year bought several dozen combat drones from Turkey, and has finally received a shipment of US-made anti-tank Javelin missiles, significantly increasing the capability of ground troops that were badly needed eight years ago.
The country’s army now has 251,000 troops and 900,000 people on reserve duty, which is more than in China and the United States, and its military budget is expected to hit an all time post-Soviet high of 133 billion hryvnias (£3.7 billion) this year.