Russian proxies in occupied eastern Ukraine shelled Ukrainian-government positions over the weekend and on Monday. The artillery barrage killed two civilians and wounded several others in Sartana, near the Sea of Azov. It’s one of the larger-scale escalations of the conflict since a winter cease-fire. Meanwhile, the Obama Administration continues to withhold a radar upgrade that would allow Ukrainian forces to protect against shelling.

Moscow and Kiev agreed under the Minsk II accord negotiated in February to cease hostilities, create a buffer zone and withdraw heavy weapons. Yet “to a big extent [the Russian side] continually violates the agreement,” Gen. Viktor Muzhenko, the chief of staff of Ukraine’s armed forces, told us in a rare interview before the latest escalation. “Some days we can have 80 to 100 violations.”

Russian violations range from small-arms fire to covert infiltration to the heavy shelling on the weekend. The Kremlin’s aim is to gradually break the will of the Ukrainian people. “This war looks like a war of attrition,” Gen. Muzhenko says. “It’s Russia’s intent to demoralize our forces, and using that mechanism they want to influence Ukraine’s military leadership as well as the state leadership.”

The devastation and human suffering wrought by indiscriminate Russian shelling—120 mm mortars and 152 mm howitzers that blow through homes, factories and fortifications and account for many of the nearly 9,000 killed since the conflict erupted—is at the heart of this strategy. Under pressure from the U.S. and Western European powers to abide by Minsk while its adversary doesn’t, Kiev’s hands are tied and its capabilities are outmatched by the Kremlin’s.

The Obama Administration refuses to provide lethal assistance to Kiev, and even previously promised nonlethal assistance isn’t always forthcoming. The Journal reported in July that the Pentagon was considering transferring the AN/TPQ-36 and 37 Firefinder radar system to Ukraine. The system would allow Kiev to better surveil Kremlin-held territory, and to locate and silence the sources of incoming artillery fire.