Ukrainian President Volodymyr Zelenskyy declared Martial Law on Thursday across the country, according to NBC News translation, after Russian President Vladimir Putin launched a massive military operation targeting Ukraine.

Explosions were heard across Kyiv shortly after Putin’s address to the Russian people. The move ended all hopes of a diplomatic solution with the United States and its western allies.

Zelenskyy says he tried to call the Russian leader but was rebuffed.

Ukraine’s foreign minister said in a tweet that the country was prepared to defend itself in the face of Russian aggression.

“Don’t panic, we’re strong, we’re prepared, we will win,” Zelenskyy told citizens on Thursday.