Russia’s month-long war on Ukraine has killed thousands of people, displaced millions of refugees and devastated cities, but its armed forces remain largely frustrated by fierce Ukrainian resistance, with no end in sight to the conflict.

On February 24, Russian President Vladimir Putin launched a full-scale invasion of Ukraine – the biggest offensive in Europe since World War II – and implied the possibility of nuclear escalation if the West intervened.

After Russian armed forces were unable to seize control of Ukraine with a lightning offensive in the first week of the war, they shifted strategy to the bombardment of cities with artillery, air strikes and missiles. Civilian targets including hospitals, churches and housing have been hit, leading United States President Joe Biden to call Putin a "war criminal”.

Russian forces have repeatedly struck the capital, Kyiv, but have failed to encircle the city.

The besieged southern port city of Mariupol has been hardest hit, subject to weeks of bombardment that has killed at least 2,300 people and destroyed most of the city, according to Ukrainian officials. About 100,000 civilians remain trapped in the city without running water, electricity, or heating, and with supplies of food dwindling.

Only one major city, Kherson, has fallen to the Russians.

The war’s death toll is unclear, but Ukrainian President Volodymyr Zelenskyy – who has become a symbol of national resistance – said on Wednesday that thousands of people have been killed, including at least 121 Ukrainian children.

Ukraine says it has killed 14,000 Russian soldiers, and destroyed hundreds of tanks, armoured vehicles, artillery pieces and aircraft. Even conservative US assessments estimate at least 7,000 Russian dead.

The United Nations says more than 3.6 million Ukrainians have now fled the country, and a further 6.5 million have been displaced within Ukraine.

The war has also rattled the global economy and the geopolitical order.

Economic sanctions on a scale never before placed on a $1.5 trillion economy are set to send Russia into deep recession this year. The World Bank warns the country is now in "default territory”.

Biden travels to Europe on Wednesday with new sanctions proposals, including weighing whether Russia could be kicked out of the Group of 20 (G20) bloc of nations.

However, the Kremlin insists that its war is going to plan and that Russia will not stop fighting until it has achieved its strategic goals – including forcing Ukraine to become "neutral” and "demilitarise”.