(The Hill) – The U.S. Embassy in Kyiv sounded the alarm on a "potential significant air attack" Wednesday, announcing that it will close. The warning also recommended American citizens in the area to prepare to shelter in place. The release follows a drone and missile attack that officials called "the largest in recent months," The Associated Press reported. The strike killed eight people and wounded dozens, according to an official, as more than 400 people were evacuated from a nine-story building in the city of Sumy, Ukrainian Minister of Internal Affairs Ihor Klymenko said, according to the AP. Included in the security alert were actions to take, such as monitoring the media for updates, identifying possible shelters, immediately taking shelter and following directions from Ukrainian officials and first responders. A view of the U.S. Embassy in Kyiv, Ukraine, Saturday, Feb. 12, 2022. (AP Photo/Andrew Kravchenko) The alert comes in the wake of President Biden's approval for the use of Western-provided long--range missiles by Ukraine to strike targets within Russia. The decision enraged Russia and riled allies of President-elect Trump, who has previously been somewhat critical of Ukraine. On the campaign trail, Trump vowed to end the nearly three-year-long war in a day. Kremlin spokesperson Dmitry Peskov on Monday referred to comments by Russian President Vladimir Putin in September that warned Moscow would view the U.S. and NATO in direct conflict with Russia if the U.S. granted permission to Ukraine to use long-range missiles far-beyond Russia’s borders to hit targets.  “If this decision is taken, it will mean nothing less than the direct involvement of NATO countries, the United States and European countries in the war in Ukraine,” Putin said at the time.  What are ATACMS, the US-made weapons Ukraine used against Russia? Ukraine is now occupying part of Russia’s Kursk region after a surprise incursion across the border in August. For months, Ukraine and other U.S. officials have publicly lobbied Biden to lift restrictions on U.S.-made weapons systems to push Russia back and target Russian military targets across the border.  Ukraine struck the Russian region of Bryansk on Tuesday with the missiles from the Army Tactical Missile System (ATACMS) for the first time. The Associated Press contributed to this report.