Will the Putin Playbook bring 'holy hell' to citizens of Ukraine? Russian leader has horrific track record of destroying schools and hospital in Chechnya and Syria conflicts and could revert to scorched-earth policy

• Fears Vladimir Putin will 'unleash holy hell' on civilian targets in Ukraine invasion
• Russian missiles have hit Kyiv's 1,300ft TV tower, a holocaust memorial and residential apartment buildings
• Boris Johnson urged Putin not to commit 'unalterable humanitarian catastrophe'
• Tactics targeting civilians and infrastructure have been deployed by Putin before
• Russian decimated Chechen city of Grozny during independence war in 2000 
• Putin later accused of bombing hospitals and schools in Syrian Civil War
• President Volodymyr Zelenskyy slammed Putin's attacks on Ukraine's non-military targets as 'state terrorism'

Fears are rife that Vladimir Putin is turning to previous barbaric tactics of targeting civilians and levelling cities as the war in Ukraine continues to intensify.

Amid a sixth day of violence in the country, missiles hit capital Kyiv's TV station tower, knocking out some broadcasters, and destroyed a nearby holocaust memorial.

Over the weekend, yet more rockets rained down on apartment buildings in the east and banned cluster bomb munitions were reportedly being used against civilians. 

Speaking of the horrific scenes created by Russia, Former US Defense Secretary William Cohen told CNN that Putin was planning to 'lay siege to Kyiv' and 'unleash holy hell in terms of hitting civilian areas, killing hundreds if not thousands of civilians'.

Prime Minister Boris Johnson was among the first to condemn the attacks as he urged Putin not to 'Grozny-fy' Kyiv as Russian forces faced fierce resistance from brave Ukrainian fighters.

His 'Grozny-fy' comment refers to the capital city of the Chechen Republic in Russia's south which was almost completely decimated in the Second Chechen War in 2000 - at a cost of many thousands of lives.

The city was the site of chemical weapons attacks, indiscriminate bombing, and cluster bombs. 

These are the tactics of President Putin's war playbook. If things do not go to plan or there are setbacks, then he will double down with even harder force. 

Chechnya, the first major conflict of his time in power, gave the first glimpse into his unrelenting approach that was repeated in Syria, Georgia, and to a lesser extent in Crimea.

And now the threat of themobaric 'vacuum' bombs on the battlefields of Ukraine show Putin is serious.

Russian forces had already spent years suppressing the independence movement in Chechnya when, in 1999, Putin took control of Russia as Boris Yeltsin resigned. 

He immediately faced the issue of the Chechen republic, where fighters had invaded neighbouring Dagestan and claimed an independent Islamic caliphate.

Putin went on the offensive, using intensive heavy artillery and aerial bombardment campaigns to wear down their forces.

Key to victory however would be the Battle of Grozny, Chechnya's capital city and fighters with an innate knowledge of the area were bedded down to defend. 

In a chilling echo of Ukraine today, Russia was at first met with fierce heavy resistance, with the Chechens using trench systems and even the sewers to expertly defend against an advance. Whole buildings could be booby-trapped or boarded up, sprung to create a deadly ambush.

But Putin and his commanders were relentless: Grozny was first blockaded, with no ammunition, food or other supplies able to enter; artillery bombardment stretched on for weeks, killing thousands; and later both sides were accused of using chemical weapons against each other.

Grozny was eventually lost on February 6, 2000 - between 5,000 and 8,000 civilians had been killed, and every single building was damaged.  

The bombardment had been so brutal that by 2003, the United Nations was still calling Grozny the most destroyed city on earth.

But importantly for Putin the war would be the first in a string of wins during his Presidency - and he is yet to 'lose' a conflict that he has been involved in.  

'When it comes to waging war, he [Putin] is not bound by any sense of propriety or concern about how many or who are killed,' former Secretary Cohen said of Putin's tactics.

The horrors of the Russia war machine did not reach their peak however until the Syrian Civil War - which Russia joined in 2015 and for which it was found to have committed war crimes by the UN.

Putin came in on the side of President Bashar al-Assad following a request for air support.

But rather than taking on just Islamic State terrorists, Russian officials at the time said they would help the Syrian government retake territory from various anti-government and rebel groups.

Employing the same scorched-earth policy as in Chechnya to find and kill rebel groups, Putin's forces began a series of airstrikes and bombing campaigns that would kill thousands.

Amnesty International and other human rights groups reported Syria and Russia targeting and destroying several hospitals and schools.

One group found that between 17 September and 13 October, 2015, 36 Russian strikes hit only two ISIS targets and 22 civilian targets including hospitals, a fire hall, at least one school. There were 70 civilian deaths. 

The UK-based pro-opposition Syrian Observatory for Human Rights (SOHR) said that between the initiation of the intervention in September 2015 and February 2016, Russian air strikes killed at least 1,700 civilians, including more than 200 children.

Ukraine is now the latest country to face a Russian invading force - and the full cost of life and physical destruction will not be known for months.

Yesterday, in one of their strikes on Ukrainian targets, Russia hit the Babyn Yar holocaust memorial in Kyiv - the site of one of the biggest single massacres of Jews during the Holocaust.

The memorial had been built by the ravine where nearly 34,000 Jews were killed by SS troops in two days in 1941 during Adolf Hitler's campaign against the Soviet Union. 

After the latest attack, Volodymyr Zelensky tweeted: 'To the world: what is the point of saying 'never again' for 80 years, if the world stays silent when a bomb drops on the same site of Babyn Yar? At least 5 killed.'

Much like with Putin's use of tactics, Zelensky ended by warning of 'history repeating' itself.