Heraldo de Madrid - Russia's Putin launches invasion of Ukraine

Weeks of intense diplomacy and the imposition of Western sanctions on Russia failed to deter Putin, who had massed between 150,000 and 200,000 troops along the borders of Ukraine.

"I have made the decision of a military operation," Putin said in a surprise television announcement that triggered immediate condemnation from US President Joe Biden and other Western leaders, and sent global financial markets into turmoil.

Shortly after the announcement, explosions were heard in Ukraine's capital, Kyiv, and several other cities, according to AFP correspondents.

Ukrainian border guards said Russian ground forces had crossed into Ukraine.

Ukraine's President Volodymyr Zelensky declared martial law and said Russia was attacking his country's "military infrastructure", but urged citizens not to panic and vowed victory.

- City residents take shelter -

Kyiv's main international airport was hit in the first bombing of the city since the Second World War and air raid sirens sounded over the capital at the break of dawn.

"I woke up because of the sounds of bombing. I packed a bag and tried to escape. We are sitting here, waiting," said Maria Kashkoska, as she sheltered inside the Kyiv metro station.

Ksenya Michenka looked deeply shaken as she took cover with her teenage son.

"We need to save our lives," she said.

Ukraine's foreign minister said the worst-case scenario was playing out.

"Putin has just launched a full-scale invasion of Ukraine. Peaceful Ukrainian cities are under strikes," Dmytro Kuleba tweeted.

"This is a war of aggression. Ukraine will defend itself and will win. The world can and must stop Putin. The time to act is now."

Within a few hours of Putin's speech, Russia's defence ministry said it had neutralised Ukrainian military airbases and its air defence systems.

- 'Unprovoked and unjustified' -

In his televised address, Putin justified the operation by claiming the government was overseeing a "genocide" in the east of the country.

The Kremlin had earlier said rebel leaders in eastern Ukraine had asked Moscow for military help against Kyiv.

Biden, who had for weeks sought to lead a Western alliance to deter Putin from invading Ukraine, spoke with Zelensky after the Russian operation began to vow US "support" and "assistance".

Biden condemned the "unprovoked and unjustified attack by Russian military forces," and urged world leaders to speak out against Putin's "flagrant aggression".

He also vowed Russia would be held accountable.

"President Putin has chosen a premeditated war that will bring a catastrophic loss of life and human suffering," he said in a statement.

Biden was due to join a virtual, closed-door meeting of G7 leaders -- Britain, Canada, France, Germany, Italy, Japan and the United States -- on Thursday.

The G7 meeting is likely to result in more sanctions against Russia, which had long claimed it would not invade Ukraine, despite massing troops on the country's borders.

NATO member Poland said it was invoking Article 4 of the NATO Treaty, calling for urgent consultations among leaders of the Western military alliance.

- 'Aggression' -

An excuse for the military operation was given on Wednesday when the Kremlin said the separatist leaders of Donetsk and Lugansk had sent letters to Putin, asking him to "help them repel Ukraine's aggression".

Their reported appeals came after Putin recognised their independence and signed friendship treaties with them that include defence deals.

The United Nations Security Council had met late Wednesday for its second emergency session in three days over the crisis, with a personal plea there by UN Secretary-General Antonio Guterres coinciding with Putin's announcement.

"President Putin, in the name of humanity, bring your troops back to Russia," Guterres said.

"Do not allow to start in Europe what could be the worst war since the beginning of the century."

French President Emmanuel Macron condemned Russia's decision to "wage war on Ukraine" and said France would work with its allies to "end the war".

Japanese Prime Minister Fumio Kishida said the attack "shakes the foundation of the international order" and British Prime Minister Boris Johnson called a crisis meeting in London.

The US ambassador to the United Nations, Linda Thomas-Greenfield, warned that an all-out Russian invasion could displace five million people, triggering a new European refugee crisis.

The Russian ruble fell nine percent against the dollar after the attack and the Moscow Stock Exchange plunged almost 14 percent.

- Living in fear -

Western nations said ahead of Thursday's operation, Russia had amassed 150,000 troops in combat formations on Ukraine's borders with Russia, Belarus and Russian-occupied Crimea and on warships in the Black Sea.

Ukraine has around 200,000 military personnel, and could boost that with up to 250,000 reservists.

Moscow's total forces are much larger -- around a million active-duty personnel -- and have been modernised and re-armed in recent years.

But Ukraine has received advanced anti-tank weapons and some drones from NATO members. More have been promised as the allies try to deter a Russian attack or at least make it costly.

Speaking to journalists, Putin on Tuesday set out a number of stringent conditions if the West wanted to de-escalate the crisis, saying Ukraine should drop its NATO ambition and become neutral.

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D.Prieto--HdM