• Explosions heard across the country
• Tanks and troops enter Ukraine
• Ukraine says it is fighting back

Moscow and Kyiv (CNN): Russian forces have begun an attack on Ukraine, with reports of troops crossing the border to the north and south, explosions in multiple cities including the capital Kyiv and warnings from Russian President Vladimir Putin of bloodshed unless Ukrainian forces lay down their arms. 

The offensive that Russia called a “special military operation” came as world leaders attempted to avert catastrophe with a meeting of the United Nations Security Council amid warnings that a possible invasion could start the biggest war in Europe since 1945.

The first blasts were heard at around 5 a.m. Thursday, prompting immediate condemnation from the United States and its allies, which have threatened to enact “full scale” sanctions in response to Russian military aggression.
As air raid sirens rang out across Kyiv early Thursday, Ukrainian President Volodymyr Zelensky moved to enact martial law and government ministers accused Moscow of launching a “full-scale invasion.” As dawn broke, heavy traffic could be seen clogging roads heading west out of the city, while further east, near the Russian border, the mayor of Kharkiv urged citizens not to leave their homes.  Ukraine’s Foreign Minister Dmytro Kuleba tweeted on his official page that “peaceful Ukrainian cities are under strike” and called the situation “a war of aggression.” And an adviser to the Ukrainian Interior Minister, Anton Gerashchenko, told journalists Russia’s “invasion has begun” with “missile strikes on Kyiv.”

• The first blasts were heard at around 5 a.m. Thursday, prompting immediate condemnation from the United States and its allies