WASHINGTON (NewsNation Now) — President Volodymyr Zelenskyy declared martial law Thursday and announced the country cut diplomatic ties with Moscow as Russia launched its attack on Ukraine.

Zelenskyy’s actions came in a second video message that he posted to social media as Russian troops were entering his country.

“Russia has attacked our military infrastructure and our border guards,” Zelenskyy said. “Explosions were heard in many cities of Ukraine. We introduce martial law throughout the state.”

He told Ukrainians that the United States was gathering international support to respond to Russia.

Ukrainians who had long braced for the prospect of an attack were urged to stay home and not to panic, even as officials said Russian troops were rolling into Ukraine, and big explosions were heard in the capital of Kyiv, Kharkiv in the east and Odesa in the west.

In an earlier video address, Zelenskyy made a plea to Russian citizens as he explained his views on Russian aggression toward Ukraine, saying he doesn’t want a war but that his country will defend itself.

“We have no need for another cold war, or a bloody war, or a hybrid war,” Zelenskyy said.

In an apparent reference to Russian President Vladimir Putin’s move to authorize the deployment of the Russian military to “maintain peace” in eastern Ukraine, Zelensky warned that, “This step could mark the start of a big war on the European continent.”

“Your leadership approved for them to take a step further, in the territory of another country. This step can become the beginning of a great war on the European continent,” Zelenskyy said.

He continued, “Any provocation, any spark could trigger a blaze that will destroy everything.”

However, Zelenskyy’s pleas proved unsuccessful.

The attack began even as the U.N. Security Council held an emergency meeting to hold off an invasion. Members still unaware of Putin’s announcement of the operation appealed to him to stand down. U.N. Secretary-General Antonio Guterres opened the meeting, just before the announcement, telling Putin: “Give peace a chance.”

European Council President Charles Michel and European Commission President Ursula von der Leyen later promised to hold the Kremlin accountable.

“In these dark hours, our thoughts are with Ukraine and the innocent women, men and children as they face this unprovoked attack and fear for their lives,” they said on Twitter.

Zelenskyy made it clear Ukraine intends to fight this will not be a repeat of 2014 when Russia took Crimea without firing a shot. Overnight, he told Ukrainians that the government would arm anyone willing to fight.