It said the 5.5-ton Kh-22 missiles, when used in ground attacks with conventional warheads, are highly inaccurate and can cause severe collateral damage and casualties.
Russia is likely using such weapons because it is running short of more precise modern missiles, Britain’s Defense Ministry said in a daily update. It gave no details of where exactly such missiles are thought to have been deployed and there was no immediate confirmation from Ukrainian authorities of the use of the heavy missiles.
Both sides have been expending large amounts of weaponry in what has become a grinding war of attrition for the eastern region of coal mines and factories known as the Donbas, placing huge strains on their resources and stockpiles.
The area borders Russia and has been partly controlled by Moscow-backed separatists since 2014.
The report from the British Defense Ministry said Ukrainian air defenses were still deterring Russian tactical aircraft from carrying out strikes across much of the country.
Meanwhile, the Ukrainian army said Russian forces were regrouping to launch an offensive on the city of Sloviansk in Ukraine’s eastern Donetsk region.
In its regular operational update, the General Staff of the Armed Forces of Ukraine said Moscow managed to get a foothold overnight in the village of Bohorodychne, 24 kilometers (about 15 miles) northwest of Sloviansk, and was preparing to attack the city.
The update said that the threat of missile and airstrikes on Ukraine from Belarusian territory remains, noting that Minsk extended military exercises along the Ukrainian-Belarusian border until June 18.
Elsewhere, the Donetsk regional police said Russian missiles hit 13 towns and villages in the region overnight. In a statement, the police said that civilians had been killed and wounded, without specifying numbers.