Why has Russia invaded Ukraine and what does Putin want?

Vladimir Putin unleashed the biggest war in Europe since World War Two with the justification that modern, Western-leaning Ukraine was a constant threat and Russia could not feel "safe, develop and exist".

Thousands of people have since died, towns and cities such as Mariupol lie in ruins and 13 million people have been displaced. But the questions remain: what was it all for and how will it end?

What was Putin's original goal?

The Russian leader's initial aim was to overrun Ukraine and depose its government, ending for good its desire to join the Western defensive alliance Nato. After a month of failures, he abandoned his bid to capture the capital Kyiv and turned his ambitions to Ukraine's east and south.

Launching the invasion on 24 February he told the Russian people his goal was to "demilitarise and de-Nazify Ukraine". His declared aim was to protect people subjected to what he called eight years of bullying and genocide by Ukraine's government. Another objective was soon added: ensuring Ukraine's neutral status .

Foreign Minister Sergei Lavrov spoke of freeing Ukraine from oppression while foreign intelligence chief Sergei Naryshkin argued "Russia's future and its future place in the world are at stake".

Ukraine's democratically elected president, Volodymyr Zelensky, said "the enemy has designated me as target number one; my family is target number two". His adviser said Russian troops made two attempts to storm the presidential compound.