Russian military forces launched a sweeping military invasion of Ukraine just before dawn on Feb. 24, with local reports showing an intense barrage of air and artillery attacks while Russian ground forces streamed across Ukraine’s northern, eastern and southern borders.

The initial wave of bombardment by Russian aircraft, cruise missiles and rockets appeared to target at least five major cities in all parts of the country, including Kyiv, Kharkiv, Odessa, Ivano-Frankivsk, and Mariupol, according to the U.S. embassy in Ukraine. 

Russian attacks targeted airfields for squadrons of Ukrainian Air Force MiG-29s, Su-27s and L-39s, along with anti-aircraft missile units operating S-300 systems, the Ukraine Ministry of Defense says in a statement. 

One Ukrainian Su-27 appeared to flee to Romania in the first minutes of the Russian assault. Two Romanian F-16s escorted the Ukrainian Su-27 to land at the 95th Air Base near Bacau in northeast, Romania, the Romanian Ministry of Defense said in a news release, adding that the Su-27 pilot surrendered.

In the early hours of the morning, Ukrainian and Russian leaders ordered the closure of the airspace over Ukraine to civilian air traffic, as videos on social media showed attacks by air defenses on what appeared to be military aircraft. 

The European Union Aviation Safety Agency said Ukraine was now an “active conflict area” and that the “presence and possible use of a wide range of ground and airborne warfare systems poses a high risk for civil flights operating at all altitudes and flight levels.”

Ukraine President Volodymyr Zelenskyy imposed martial law in response to the Russian attacks on what he called military facilities and border posts.  

He described the Russian operation as an “unjustified deceitful and cynical invasion,” adding: “Ukrainians will never give up their freedom and independence to anyone.” 

Kyiv has subsequently severed all diplomatic relations with Moscow. 

The Russian attacks have drawn widespread condemnation, with countries announcing plans to ramp up sanctions against Moscow. 

NATO Secretary General Jens Stoltenberg called on Russia to cease attacks on Ukraine immediately, calling the invasion a “grave breach of international law, and a serious threat to Euro-Atlantic security.”

“Russia alone is responsible for the death and destruction this attack will bring, and the United States and its Allies and partners will respond in a united and decisive way,” U.S. President Joe Biden said, adding, “The world will hold Russia accountable.” Biden said he would meet on Feb. 24 with leaders of the G7. 

Russian President Vladimir Putin announced the operation with a lengthy address, saying the goal is to “demilitarize” Ukraine and roll back the encroachment of NATO forces and allies on Russia’s borders.  

Belarusian president Aleksandr Lukashenko said his country’s armed forces were not involved in the Russian operation, even though Minsk has provided bases for the invading Russian forces.