KYIV, Ukraine — The Ukrainian military on Tuesday reported destroying a Russian ammunition depot in southern Ukraine, resulting in a massive explosion captured on social media, while authorities said the death toll from a weekend Russian strike in the country’s east grew to 41.

An overnight rocket strike targeted the depot in Russian-held Nova Kakhovka, the Ukrainian military’s southern command said. Nova Kakhovka is located about 35 miles east of the Black Sea port city of Kherson, which is also occupied by Russian forces.

The precision of the strike suggested Ukrainian forces used U.S-supplied multiple-launch High Mobility Artillery Rocket Systems, or HIMARS, to hit the area. Ukraine indicated in recent days that it might launch a counteroffensive to reclaim territory in the country’s south as Russia bombards the eastern Donbas region.

Russia’s Tass news agency offered a different account of the blast in Nova Kakhovka, saying a mineral fertilizer storage facility exploded, and that a market, hospital, and houses were damaged in the strike. Some of the ingredients in fertilizer can be used for ammunition.

A satellite photo taken Tuesday and analyzed by The Associated Press showed significant damage. A massive crater stood precisely where a large warehouse-like structure once stood in the city,

Ukraine now has eight of the HIMAR systems, a truck-mounted missile launcher with high accuracy, and Washington has promised to send another four.

Russian Shelling Continues

Elsewhere in Ukraine, Russian shelling over the past 24 hours killed at least 16 civilians and wounded 48 more, Ukraine’s presidential office said in its Tuesday morning update. Cities and towns in five southeast regions came under Russian fire, the office said.

Nine civilians were killed and two more wounded in Donetsk province, which makes up half of the Donbas. Russian rocket attacks targeted the cities of Sloviansk and Toretsk, where a kindergarten was hit, the presidential office said.

The British military said Tuesday that Russia was continuing to make “small, incremental gains” in Donetsk, where heavy fighting led the province’s governor last week to urge its 350,000 remaining residents to move to safer places in western Ukraine.

The death toll from a Russian rocket attack that struck a Donetsk apartment building Saturday rose to 41, the emergency services agency said Tuesday afternoon. It said four more bodies were found and nine people were rescued from the rubble of the building in Chasiv Yar.

Yet many in the Donbas, a fertile industrial region in eastern Ukraine made of Donetsk and Luhansk provinces, refuse — or are unable — to flee, despite scores of civilians being killed and wounded each week.

Putin Schedules Visit to Iran

The Kremlin said Russian President Vladimir Putin would visit Iran next week. Kremlin spokesman Dmitry Peskov said that Putin will travel to Tehran next Tuesday to attend a trilateral meeting with the leaders of Iran and Turkey, a format for Syria-related talks. U.S. National Security Adviser Jake Sullivan told reporters on Monday that Russia was seeking hundreds of surveillance drones from Iran, including weapons-capable ones, for use in Ukraine.