A former Miss Ukraine has joined the fight against Russia.

Anastasiia Lenna dressed herself in military gear and recorded footage of her training on Instagram, as tens of thousands of Ukrainian volunteers responded to their country's call to sign up and fight Vladimir Putin's invasion.

Ms Lenna, who represented her country in the 2015 Miss Grand International beauty contest, wrote: 'The invaders will die on our land. All world see this.'

She has posted various other messages warning Russian forces about invading and encouraging her fellow Ukrainians.

Ms Lenna speaks five languages and has worked as a translator, as well as a model and public relations manager in Turkey, after graduating with a marketing and management degree, Sky News reported.

Ukrainians have volunteered en masse to help defend the capital Kyiv and other cities, taking guns distributed by authorities and preparing firebombs to fight Russian forces.

Online tutorials have been teaching many how to make Molotov cocktails, while all men of military age have been banned from leaving the country in an effort to get more fighters.

Ms Lenna represented her country in 2015 (Picture: instagram.com/anastasiia.lenna)
She has worked as a translator and speaks five languages (Picture: instagram.com/anastasiia.lenna)
She says she has started training and told Russian invaders they would die in Ukraine (Picture: instagram.com/anastasiia.lenna)
Ms Lenna is one of countless Ukranians to sign up to help (Picture: instagram.com/anastasiia.lenna)

Among the other volunteers is boxing champion turned Kyiv Mayor, Vitaly Klitschko.

He told the Russian invaders to 'go home' while dressed in full military kit.

Ukraine is also releasing prisoners with military experience who want to fight for the country, authorities said.

It comes as fierce street fighting broke out in Ukraine's second city, Kharkiv, as Russian forces continue to advance on Kyiv.

Former Miss Ukraine Anastasiia Lenna in a plunging red dress - long before she took up arms against Russian invaders

Until Sunday, Russia's troops had remained on the outskirts of Kharkiv, a city of 1.4 million about 12 miles south of the Russian border.

Videos posted on Ukrainian media and social networks showed Russian vehicles moving across Kharkiv and Russian troops roaming the city in small groups.

Russian forces blew up a gas pipeline in the city, prompting the government to warn people to cover their windows with damp cloth or gauze as protection from smoke, the president's office said.

Strategic ports in the country's south are also coming under attack – but stern resistance from the Ukrainians has slowed the advance.

Earlier on Sunday, Kyiv was eerily quiet after huge explosions lit up the morning sky and authorities reported blasts at one of the airports.

Only an occasional car appeared on a deserted main boulevard as a strict 39-hour curfew kept people off the streets.

A Russian Defence Ministry spokesman, Major General Igor Konashenkov, said Russian forces had blocked the cities of Kherson on the Black Sea and the port of Berdyansk on the Azov Sea.

He said the Russian forces also took control of an airbase near Kherson and the Azov Sea city of Henichesk.

Cutting Ukraine's access to its sea ports would deal a major blow to the country's economy.

The country's authorities have also reported fighting near Odesa, Mykolaiv and other areas.

Volunteers, among them the former Miss Ukraine Anastasiia Lenna (pictured), have taken up arms to fight off Vladimir Putin's army in Kyiv after the city held firm in a third night of 'brutal' shelling

The number of casualties so far from Europe's largest land conflict since the Second World War remains unclear amid the fog of combat.

Ukraine's health minister reported on Saturday that 198 people, including three children, had been killed and more than 1,000 others wounded.

It was unclear whether those figures included both military and civilian casualties.

Russia has not released any casualty information but claimed losses were 'many times' lower than Ukraine's – though Ukraine claims it is actually far higher.