Russian forces lost 2,520 fighters, more than 200 vehicles and over 100 artillery systems in 48 hours, according to figures published by Ukraine's military, as Moscow sustains the pressure on Ukraine's defenses in the north and the east at a heavy cost.

The Kremlin's troops sustained more than 2,500 casualties between early Saturday and Monday morning local time, tallies published by Kyiv's armed forces indicate. Between Saturday and Sunday, Russia lost 1,320 fighters, Ukraine's General Staff said.

Since Saturday, Moscow has lost 15 tanks, 47 armored personnel vehicles and 162 other vehicles and fuel tanks, Ukraine said. Kyiv's military also said Russia had lost 108 artillery systems in the same period.

Newsweek could not independently verify Ukraine's numbers and has reached out to the Russian Defense Ministry for comment via email.

Pinning down accurate casualty counts and battlefield losses during active conflicts is notoriously difficult, and experts urge caution when dealing with tallies offered up by either party in a war.

Neither Russia nor Ukraine regularly nod to the toll their war effort is taking on their own armed forces. Kyiv's losses and casualties have also been substantial, although exact numbers are not clear.

In late February, Ukrainian President Volodymyr Zelensky said 31,000 Ukrainian troops had been killed in two years of war. Russia has said Ukraine's death toll is much higher, saying Kyiv lost 215,000 soldiers in 2023 alone.

Russia has made slow but steady gains, particularly in the heart of the fighting in eastern Ukraine, in recent months, but at a huge cost to its personnel. Western intelligence and experts suggest many of the Russian soldiers currently on the front lines have limited training—often volunteers or convicts—and cannot carry out complex operations.

While fighting blazed on in the east, Russia also launched a cross-border offensive into Ukraine's northeastern Kharkiv region in early May. Ukraine quickly said Moscow hoped to pull scarce resources from Ukrainian positions along the eastern front to the northern border with Russia, overstretching Kyiv to advance in the east.

By the end of the month, the U.K. government said Russia's total casualties had likely reached 500,000, and May marked the highest average daily Russian casualty count of the more than two years of war.

During May and June combined, Russia likely sustained more than 70,000 casualties, the British Defense Ministry said on Friday.

"Russia's casualty rate will likely continue to average above 1,000 a day over the next two months as Russia continues to try to overmatch Ukrainian positions with mass," the British government evaluated.

Ukraine has said Russia is able to pull up to 30,000 new soldiers each month into its ranks to replenish its heavy losses, roughly matching the number of casualties Moscow's military is sustaining every month.