Russian forces pressed the attack in eastern Ukraine on Saturday but failed to capture their three main objectives, the Ukrainian military said, according to Reuters.

Per the general staff of Ukraine’s armed forces, the Russians were attempting to capture the city of Lyman in the Donetsk Oblast and the cities of Sievierodonetsk and Popasna in the Lukahsk Oblast.

The Pentagon said Russian forces are making only “plodding progress” in the face of intense Ukrainian resistance, Washington Post reported.

According to Reuters, “Moscow said on Saturday its artillery units had struck 389 Ukrainian targets overnight.” Artillery has played a major role on the eastern front, with some observers warning that Ukraine may not have enough artillery rounds to keep pace with Russia’s bombardment.

Russia’s ongoing campaign in the Donbas, which it launched after failing to take Kyiv, aims to capture territory in eastern and southern Ukraine. A Russian general said earlier this month that Russia hopes to establish land bridges connecting the eastern separatist republics to Crimea and Moldova, a goal that would require seizing virtually all of southern Ukraine.

The largest obstacle separating Russian forces from the Moldovan border is the port city of Odessa. On Saturday, The Kyiv Independent reported that Ukrainian police believe Russia has hired “criminal gangs to plot provocations and riots in Odessa” on May 2. In response, Odessa police have declared a curfew “from the evening of May 1 till May 3.”