At least four people were killed in a Russian attack, Ukraine said, amid concerns about air defenses after the U.S. said it was suspending military and intelligence aid.

Before the recent restrictions imposed by the U.S., a rising tempo of Ukrainian strikes inside Russia – such as those targeting stores of ammunition — relieved pressure on Ukrainian troops on the front lines. It is one of the reasons Russia’s advances in eastern Ukraine have slowed in recent weeks, analysts say.

Ukrainian President Volodymyr Zelensky on Saturday called for more sanctions against Russia as overnight strikes killed at least 14 people and wounded dozens more, days ahead of talks between US