Warnings of a wider war as analysts fear swift occupation of Ukraine

Kiev says Russian ground forces have crossed the border as Nato looks on

Firefighters arrive at a military building in Kiev that was damaged in an explosion. EPA

A man looks at the debris of an unidentified object in the aftermath of an explosion in Kiev. EPA

Black smoke rises from a military airport in Chuguyev near Kharkiv. AFP

People take shelter in a Kiev subway station, after Russian President Vladimir Putin authorised a military operation in eastern Ukraine. Reuters

A Kiev underground train station provides some shelter. Reuters

Clear airspace over Ukraine, shortly after the attack began, as shown on the Flightradar24 website. AP

Kiev residents leave the city following pre-offensive missile strikes by the Russian armed forces and Belarus. Getty

Russian President Vladimir Putin justified the attack in a televised address, saying it was to protect civilians in eastern Ukraine. AP

Ukrainian President Volodymyr Zelenskyy addresses the nation in Kiev. He has declared martial law, saying Russia has targeted Ukraine's military infrastructure. AP

Firefighters extinguish a blaze at a house in Muratovo, in Ukraine's Luhansk enclave. AFP

The house is said to have been hit during shelling by Russian-backed separatists. AFP

The coffin of Capt Anton Sidorov is carried by members of the honour guard during a ceremony held at the Ministry of Defence in Kiev, Ukraine. Getty

A picture memorial for those killed in the confrontation between Ukraine's military and pro-Russia separatist forces, in the Luhansk region in eastern Ukraine. AP

UN Secretary General Antonio Guterres and Russia's Ambassador to the UN, Vassily Nebenzia, attend a Security Council meeting in New York to discuss the crisis in Ukraine. Reuters

Ukraine's UN ambassador Sergey Kyslytsya speaks during an emergency meeting of the Security Council. AP

US Army soldiers from the 82nd Airborne Division head towards an air base near Arlamow, Poland. Reuters

An employee works at the gun counter of a tactical equipment shop in Kiev, Ukraine. Getty

A Ukrainian soldier speaks on a walkie-talkie at his position at the line of separation between Ukraine-held territory and rebel-held territory near Svitlodarsk, eastern Ukraine. AP

A man removes his belongings from his house after it was struck by artillery shells in Novoluhanske, eastern Ukraine. AP

A damaged house in Vibrovka village. EPA

A man shows a poster in support of Ukraine as he protests against the escalation of the tension between Russia and Ukraine, in Berlin. AP

Soldiers carry the coffin of Capt Anton Sydorov, 35, after he was killed in eastern Ukraine. AP

Workers look into a destroyed house after shelling near the city of Novoluhanske in Donetsk. Reuters

Destroyed buildings in Krasnogorivka, Ukraine. AFP

Smoke rises from a power plant after shelling outside the town of Schastia, a day after Moscow recognised two Ukrainian separatist republics and ordered the Russian Army to send in troops as ‘peacekeepers’. AFP

A Ukrainian Army soldier trudges through the wintry streets of Schastia on patrol. AFP

Three women run for cover during shelling in Schastia, eastern Ukraine. AFP

Russian tanks and armoured vehicles on the road in Rostov. EPA

A woman shares food with dogs in Stanytsia Luhanska, a crossing point between Ukrainian government-controlled areas and pro-Russian separatists' territory. AP

People wave Russian flags in Donetsk, the territory controlled by pro-Russian militants, in eastern Ukraine. AP

A tank drives along a street in the city of Donetsk. Reuters

Ukrainian President Volodymyr Zelenskyy addresses the nation on TV and says 'we are not afraid' after Russian President Vladimir Putin ordered troops into Donetsk and Luhansk, two Moscow-backed rebel regions of Ukraine. AFP

A military truck in Donetsk after Mr Putin ordered the deployment of Russian troops to the city. Reuters

Russian state television showed Mr Putin signing a decree recognising the independence of the two Ukrainian breakaway regions. Reuters

US President Joe Biden signs an executive order at the White House to prohibit trade and investment between US individuals and the two breakaway regions of eastern Ukraine. Reuters

Mr Putin signs documents, including the decree recognising two Russian-backed breakaway regions in eastern Ukraine. Reuters

Ukraine ambassador to the United Nations, Sergiy Kyslytsya, addresses an emergency meeting of the UN Security Council on the situation between Ukraine and Russia in New York. EPA

Live updates: follow the latest news on Russia-Ukraine

A former Nato commander expressed concern over a conflagration beyond Ukraine as analysts said Russia could move quickly to attack Kiev after launching an invasion of Ukraine.

Gen Sir Richard Shirreff said that Britain could soon be at war with Russia because any incursion into Nato territory would bring Britain into direct involvement in the conflict.

“There is no surprise and there is profound sadness and a sense of appalling horror at what is about to unfold for the people of Ukraine,” he said.

Britain was among the countries preparing a response after weeks of western threats and an escalation of sanctions in recent days failed to deter a Russian invasion.

Gen Shirreff, a former deputy supreme commander of Nato, said Britain had to “assume the worst” about Russia’s intentions.

“The Russians don’t hang around. They’ll look to establish overwhelming force,” he told BBC Radio 4’s Today programme.

“There will be multiple attacks from different axes … a full-blown military offensive to occupy Ukraine.

"I think we have to assume that this is not Russia biting off a chunk of Ukraine – for example, establishing a land corridor in Crimea – but a full-blown military offensive to occupy Ukraine.”

Gen Shirreff said it is “entirely plausible” that Russian President Vladimir Putin could be aiming to revive the Soviet Union. He said that if Russia puts “one bootstep” into Nato territory, the entire alliance will be at war.

Asked whether Britain might be expected to take part directly in the current military confrontation, he said: “Absolutely there is a possibility that we as a nation could be at war with Russia, because if Russia puts one bootstep across Nato territory, we are all at war with Russia. Every single one, every single member of the Nato alliance.

“Article 5 [of the Nato alliance] says an attack on one is an attack on all, so we need to change our mindset fundamentally, and that is why I say our defence starts in the UK on the frontiers of Nato.”

Franz-Stefan Gady, a military expert at the International Institute for Strategic Studies, predicted that Russian forces would “try everything to surround and smash the Ukrainian forces in several rapid pincer movements”.

He said Russian troops were fighting under the shield of a nuclear deterrent after Mr Putin spoke ominously of “horrible consequences” for anyone who wages war with Russia.

Mr Putin described Russia as one of the most potent nuclear powers and boasted of its range of state-of-the-art weapons.

“Ukrainian forces will have to fight well-organised delaying battles as best they can, the hardest type of tactical ground operations,” Mr Gady said.

“Without practice, they can quickly lead to chaotic retreats and break their fighting spirit. Breaking that spirit is the main aim of the rapid Russian operations.”

Ukraine’s border guards said Russian forces were attacking the country on several fronts after entering from Belarus, Russia and annexed Crimea. The Ukrainian government said shelling was taking place across the country.

The Kremlin had earlier said rebel leaders in eastern Ukraine had asked Moscow for military help against Kiev, days after Russia recognised separatist governments there.

Alex Plitsas, an Iraq War veteran and former US security official, said there were enough Russian troops to encircle Ukrainian forces in the east.

Those Ukrainian forces would then be “cut off from resupply and defending Kiev” if Russia launches an assault on the capital, Mr Plitsas said.

Although western leaders promised diplomatic retaliation against Russia, they have said they will not wage war on Ukraine’s behalf because it is not a member of Nato.

Josh Manning, a former US intelligence analyst, told Australian television that he hoped Ukraine’s fighting spirit on its home territory would be greater than that of Russian forces drafted in from far-flung barracks.

“My hope is that they fight hard and they overcome what is going to be an onslaught of brutal proportions,” he said.

Russia is “going to come in with power and shock and awe that the world hasn’t seen in a long time”.