KYIV, Ukraine (AP) — A nighttime Russian attack destroyed trains and tracks in Ukraine’s northeastern Kharkiv region, officials said Friday, and authorities organized the evacuation of children from the area as it is being pummeled by the Kremlin’s forces in a powerful new offensive.

The overnight strike on rolling stock and railway tracks also damaged buildings, according to Ukraine’s national railway operator Ukrzaliznytsia. No injuries were reported.

Authorities have evacuated more than 11,000 people from the Kharkiv region since Russia launched an offensive there on May 10, regional Gov. Oleh Syniehubov said. Officials on Friday announced the mandatory evacuation over the next 60 days of 123 orphans and children living without their parents in the area.

Russia’s Kharkiv push appears to be a coordinated new offensive that includes testing Ukrainian defenses in the Donetsk region further south, while also launching incursions in the northern Sumy and Chernihiv regions. Russian President Vladimir Putin has said the Kremlin’s army is attempting to create a “buffer zone” in the Kharkiv region to prevent Ukrainian cross-border attacks.

Ukraine’s problems have been mounting in recent months as it tries to hold out against its much bigger foe, and the war appears to be at a critical juncture.