A giant explosion which rocked the Ukrainian city of Donetsk sparked fears of a 'tactical nuke' after pro-government forces shelled a rebel-held chemical plant.

Mobile phone footage captured the moment of the explosion, which turned the night's sky orange and was so powerful it could be heard as far away as downtown Donetsk, almost four miles away.

The blast came as diplomats predicted that Russia could target other Baltic states, if they are allowed to hold on to eastern Ukraine.

Mobile phone footage captured the moment a huge explosion rocked the Ukrainian city of Donetsk speaking fears of a nuclear weapon attack

The blast caused the night's sky to light up orange and was so powerful it could be heard as far away as downtown Donetsk

Last night, locals posting on social media speculated it could have been caused by a nuclear weapon due to the ferocity of the shelling and the impact on the chemical plant.

It also temporarily caused a mushroom cloud to hang over the city with the bombing shattering windows and shaking building foundations.

However, pro-Russian rebels said that the huge explosion was caused by Ukrainian artillery shell hitting the chemical plant, which lies in the middle of the Ukrainian industrial heartland in Donetsk.

It has long been feared that shelling would hit industrial units causing a huge explosion such as this.

Luckily, no damage or injuries were caused in the blast but the conflict between Russia-backed separatists and government forces has now killed more than 5,300 people and displaced more than a million.

Pro-Russian rebels said that the huge explosion was caused by Ukrainian artillery shell hitting the chemical plant, which lies in the middle of the Ukrainian industrial heartland in Donetsk

Fighting between pro-Russian rebels and pro-government forces loyal to Kiev has intensified in Ukraine's south east region since the new year, even though the two sides agreed a truce in September.

And now diplomats are warning that Russia could be planning to target other Baltic states with Estonian president Toomas Hendrik Ilves comparing appeasing president Vladimir Putin to that of when Nazi Germany was allowed to seize parts of the former Czechoslovakia in 1938.

He said he had no fears about a Russian invasion of his country but accepted the security environment in the Baltic area had 'dramatically changed'.

A woman cries out in anger after her apartment block in Donetsk is set on fire as a result of shelling. Fighting between the two sides in Ukraine has intensified in recent weeks

An elderly woman has to be helped to her feet after discovering that the apartment block where she lives has been damaged by shelling

He told Sky News' Murnaghan programme: 'We don't have to jump right ahead to being afraid of being invaded. That's far ahead of what we are concerned about today which is reckless and irresponsible behaviour throughout our region.'

But asked how important it was that a firm or even firmer line continue to be taken against Russia's behaviour, he replied: 'We certainly think that if you appease right now in Ukraine, we know from history that appeasement will never satisfy those that are being appeased.

'Munich '38 I think should be a lesson to all of us even today.'

Firefighters work to extinguish the blaze at the residential block. It comes as diplomats are warning that Russia could be planning to target other Baltic states

People carry bags of their possessions away from the burning building as shelling and artillery fire intensifies in Donetsk

The agreement, widely viewed as a failed attempt at appeasement, allowed Nazi Germany's annexation of portions of Czechoslovakia, creating an area referred to as the Sudetenland.

And asked whether being a member of Nato was comforting in the context of the Russian threat, the Estonian president added: 'That's one reason why we first of all worked very hard to qualify for membership.

'And why we along with the UK and another one or two countries are the only ones in Nato in Europe that fulfill the two per cent defence expenditure.'

Meanwhile John Herbst, a former U.S. ambassador to Ukraine has called for military intervention in the country.

Pro-government forces unload Grad rockets from a truck before launching them towards pro-Russian separatist forces outside Debaltseve in eastern Ukraine

Rockets are fired towards separatist forces in Ukraine. Nine Ukrainian soldiers have been killed and 26 wounded in the last 24 hours

Fighting between pro-Russian rebels and pro-government forces loyal to Kiev has intensified in Ukraine's south east region since the new year

He told the Independent: '[Putin’s] statements, his provocations against the Baltic states, against Kazakhstan, indicate his goals are greater than Ukraine. If we don’t stop Mr Putin in Ukraine, we may be dealing with him in Estonia.

'I’m not saying we will, but he has given indication that this could happen. The most important national security challenge in the world today is a rogue Kremlin and we need to stop him and Ukraine is the place to do it.'

The comments come after Foreign Secretary Philip Hammond said Vladimir Putin is behaving like a 'mid 20th-century tyrant' with the illegal annexation of Crimea.

He said the Russian President will pay a 'political and economic price' for what he is doing in the region but ruled out Britain offering arms to Ukraine.

Russian president Vladimir Putin, centre, with German Chancellor Angela Merkel and French president Francois Hollande at peace talks in the Kremlin last week. Today Mrs Merkel will brief Barack Obama about the state of the negotiations

The comments echo Prince Charles's warning last year that 'Putin is doing just about the same as Hitler'.

Meanwhile German chancellor Angela Merkel will brief U.S. president Barack Obama today about the state of peace negotiations between Ukraine and Russia.

It comes after peace talks last week between herself, Putin and French president Francois Hollande.



