Russia invades Ukraine on multiple fronts; U.S. and allies hit back ...

ProfileSectionstvFeaturedMore From NBCFollow NBC NewsExplosions rocked Ukraine’s capital and air raid sirens sounded for a second morning Friday, as a top Pentagon official told U.S. lawmakers that Russian troops had advanced to just 20 miles outside Kyiv.Chairman of the Joint Chiefs of Staff Gen. Mark Milley informed House lawmakers about the newly positioned Russian troops during an unclassified briefing Thursday, according to a source on the call.Defense Secretary Lloyd Austin described the current phase of the Russia's military operation as the tip of the spear, noting that the vast majority of Russian troops are not yet in Ukraine, one person on the call and one senior defense official said.Their assessments came after Russia attacked key cities across Ukraine, leading to hundreds of casualties and prompting a warning from the Ukrainian president that saboteurs have entered Kyiv.President Volodymyr Zelenskyy said in a statement that at least 137 people have been killed and 316 have been injured during the invasion. In a video address, he later said warned of saboteurs entering the capital."We also have information that enemy sabotage groups have entered Kyiv," Zelenskyy said, adding that "the enemy marked me as the number one target.""They want to destroy Ukraine politically by destroying the head of state," he said.Around the time of Zelenskyy's video address, an apartment building in Kyiv was hit with debris after an aircraft was shot down, according to Ukrainian officials and the country's emergency services.Explosions and shelling were first heard across major cities in Ukraine around 5 a.m. local time Thursday, minutes after Russian President Vladimir Putin gave a pre-dawn televised speech from Moscow saying he was authorizing military action. Air raid sirens were broadcast across the city, and explosions were seen and heard there and in other cities, NBC News reporters on the ground said.The missile attacks and shelling by Russian forces also targeted airfields, military depots and Ukraine’s infrastructure around the country, with dozens of Russian troops, as well as Ukrainian soldiers and civilians, killed in the fighting, Ukrainian officials said.A senior U.S. defense official said Russia had launched more than 160 missiles since the strikes began.In remarks posted on Telegram, Zelenskyy renewed his calls for Ukrainian citizens to aid the defense forces, asking everyone with military experience to offer themselves in the effort.“The sounds that we hear today are not only missile strikes, explosions and rockets — it’s the sound of the Iron Curtain falling down and closing Russia from the other civilized world,” he said.“Unfortunately, we have many losses among our heroes, but we also have the Russian military taken hostage,” he said.