KYIV, Ukraine (AP) — NATO countries haven’t delivered what they promised to Ukraine in time, the alliance’s chief said Monday, allowing Russia to press its advantage while Kyiv’s depleted forces wait for military supplies to arrive from the U.S. and Europe.

“Serious delays in support have meant serious consequences on the battlefield” for Ukraine, NATO Secretary-General Jens Stoltenberg told a news conference in Kyiv with President Volodymyr Zelenskyy.

Outgunned, Ukraine’s troops have struggled to fend off Russian advances on the battlefield. They were recently compelled to make a tactical retreat from three villages in the east, where the Kremlin’s forces have been making incremental gains, Ukraine’s army chief said Sunday. The Russian Defense Ministry claimed Monday its forces had also taken the village of Semenivka.