Ukraine crisis: Massive explosion, rebels declare full military mobilisation

Russian news agencies said a gas pipeline in Ukraine's breakaway region Luhansk caught fire. Photo / Supplied

The conflict between Russia and Ukraine is heating up, with a "powerful explosion" rocking a gas pipeline near Luhansk in eastern Ukraine.

The blast has been blamed on sabotage, according to Tatiana Bogorodko, the head of Luhanskgas, which manages the gas pipeline.

European Commission President Ursula von der Leyen said in a speech that the "world has been watching in disbelief" as Russia masses troops on the border with Ukraine.

Russia has repeatedly denied having plans to invade.

Rebels in eastern Ukraine have declared a full military mobilisation, just hours after they ordered women and children to evacuate to southern Russia because of fears of a conflict.

Nato is relocating staff from Ukraine's capital Kyiv to Lviv, in the west of the country, because of fears for their safety.

People evacuate into Russia

The leaders of two separatist republics in east Ukraine ordered women and children to flee and as soon as possible make their way to Russia.

Local citizens line up to take a train at the railway station to be evacuated to Russia. Photo / AP

Their poor and industrial rebel-controlled territories in Ukraine have been at the centre of weeks of tensions between Russia and the West.

Conflict monitors have warned of a sharp escalation in ceasefire violations in fighting between Ukraine's army and the separatists.

Nato moves Ukraine staff from Kyiv to Lviv

Nato is relocating staff from Ukraine's capital Kyiv to Lviv, in the west of the country, and to the Belgian capital Brussels for their safety, an alliance official said on Saturday.

"The safety of our personnel is paramount, so staff have been relocated to Lviv and Brussels. The Nato offices in Ukraine remain operational," the official told AFP, without giving numbers.

Several Western countries have already moved diplomats from Kyiv to Lviv, located near the border with Poland, in anticipation of Russian military action.

Minefields, abandoned homes

Ukraine says it is under constant pressure from Russia. Two soldiers were killed on Saturday and US President Joe Biden says US intelligence indicates that Russia plans to invade.

One of the dead, 35-year-old Captain Anton Sidorov and father-of-three, was shot dead near Novoluganske, the scene of the minister's shelling incident.

If the more than 150,000 Russian soldiers Kyiv and Washington say are massed on the border do launch an assault, they will have to pass through frontline communities like Novoluganske.

A Ukrainian serviceman sits in an observation point near the frontline village of Krymske. Photo / AP

Andriy, a 26-year-old infantryman, is based there, and confirmed that the situation is "heating up".

"The situation is even worse than yesterday; they've been firing 152mm heavy artillery," he said. "There are wounded in several battalions."

There were 4000 people in the town before the conflict erupted, isolated by potholes roads and now by minefields marked by little painted red posts.

Three kilometres from the rebel frontline, the town lives in a sort of no-man's land and many of the homes have been abandoned.

Massive blasts hit Ukraine

Explosions have reportedly been heard in the Russian separatist city of Luhansk.

Part of a gas pipeline caught fire late on Friday after being struck by a "powerful explosion", Interfax news agency reported. It comes hours after a car bomb was detonated in Donetsk, eastern Ukraine.

Major General Denis Sinenkov was not believed to be in his car when the huge blast shook the separatist-held city.

It was feared to be a Kremlin-inspired "false flag" con to give Vladimir Putin his excuse to invade Ukraine – as his fighting force rose to 190,000.

A Ukrainian soldier looks at a hole from a shell fired by pro-Russian separatists in the village of Novoluhanske. Photo / AP

A security expert in Kyiv said: "It looks like a false flag. They will blame Ukraine but how would they have been able to booby trap it?"