KYIV, Ukraine (AP) — Russia launched 188 drones against most regions of Ukraine in a nighttime blitz, the Ukrainian air force said Tuesday, describing it as a record number of drones deployed in a single attack.

Most of the drones were intercepted, according to the air force, but apartment buildings and critical infrastructure such as the national power grid were damaged. No casualties were immediately reported in the 17 targeted regions.

Russia has been hammering civilian areas of Ukraine with increasingly heavy drone, missile and glide bomb attacks since the middle of the year.

At the same time, Russia’s army has largely held the battlefield initiative for the past year and has been pushing hard in the eastern Donetsk region where it is making significant tactical advances, according to Western military analysts.

Ukraine faces a difficult winter, with worries about the reliability of the electricity supply amid Russia’s attacks and how much U.S. support it can count on next year after President-elect Donald Trump takes office in January.

The air raid alert in the Kyiv region overnight lasted more than seven hours. Russia is trying to unnerve civilians and wear down their will to resist in the almost 3-year-old war.

The Russian Defense Ministry said Tuesday its forces destroyed 39 Ukrainian drones overnight over Russian regions near the border with Ukraine.

Meanwhile, Ukraine’s General Staff said Tuesday that over the past 24 hours roughly half of the clashes along the about 1,000-kilometer (600 mile) front line occurred near Pokrovsk and Kurakhove in the Donetsk region.

Ukraine has a critical manpower problem on the front line, and though the Russian army’s gains have been incremental its momentum is adding up as the Ukrainians yield ground.

The Russian advance is threatening important supply routes in Donetsk, the Washington-based Institute for the Study of War said late Monday.

Ukrainian defenses in Donetsk are not in danger of being overrun, however, the think tank said. It also noted that Russia would need to capture more than 8,000 square kilometers (3,000 square miles) of territory to achieve the Kremlin’s goal of seizing the whole of Donetsk.

In other developments, a court in Russia’s Kursk region has ordered a British national fighting with Ukraine to be held in detention pending an investigation and trial.

The ruling on the Briton, identified by state news agency Tass and other media as James Scott Rhys Anderson, was announced Tuesday by court officials, who said in an online statement that it was handed down the previous day.

The hearing took place behind closed doors in the Leninsky District Court in the city of Kursk. It wasn’t clear from the statement what charges Anderson is facing and whether he is considered a prisoner of war by the Russian authorities.

The Briton reportedly was captured in the Kursk region, where Ukrainian forces have seized territory following a lightning offensive in August.