The highways heading out of Ukraine’s capital have been choked with traffic, with residents fleeing Kyiv as Russian forces invade.

Russian president Vladimir Putin  declared war  in a pre-dawn televised address on Thursday, which was followed by an assault on Ukraine by land, sea and air.

Explosions and gunfire could be heard throughout the morning in Kyiv as missiles struck Ukrainian targets and authorities reported columns of troops entering Ukraine from Russia and Belarus.

The assault comes after weeks of Western leaders making diplomatic efforts to prevent war.

After a day of fighting, Putin told business people in Moscow that he had no choice but to act.

Meanwhile, Western leaders have condemned Moscow’s actions and promised widespread sanctions.

Ukrainian president Volodymyr Zelensky called on the people to defend their country, and said weapons would be given to anyone prepared to fight.

“What we have heard today are not just missile blasts, fighting and the rumble of aircraft,” he said.

“This is the sound of a new Iron Curtain, which has come down and is closing Russia off from the civilised world.”

After fierce fighting in the regions of Symy and Kharkiv, in Ukraine’s northeast, and Kerson and Odessa in the south, Ukraine’s ambassador to the United States said 40 servicemen and dozens of civilians had been reported killed, although the information wasn’t up-to-date.

Authorities in Odessa said 18 people were killed in a missile attack, while those in Brovary, a town near Kyiv, said at least six people had died.

Ukraine’s military said it destroyed four Russian tanks near Kharkiv, killed 50 soldiers in a town near Luhansk, and took down six Russian warplanes.

Russia has denied that any of its tanks or aircraft had been destroyed.

Even with a full-blown invasion underway, Putin’s ultimate motivations remain unclear. The Russian president said he didn’t plan a military occupation, only to disarm Ukraine and rid it of nationalists.

However, a senior US defence official said Washington believed the invasion was intended to “decapitate” Zelensky’s government.

EU leaders are due to meet to agree on further sanctions against Russia that will have “massive and severe” consequences for Moscow, according to a draft of their summit conclusions seen by Reuters.

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