He suggested the pause begin this Thursday, which is Holy Thursday for Orthodox Christians.

U.N. Secretary-General Antonio Guterres appealed on Tuesday for a halt in fighting in Ukraine during Orthodox Christians’ Holy Week, invoking Easter to plead for a four-day “pause” to allow humanitarian aid and evacuations.

Noting that the Easter season is coming amid an intensifying Russian offensive in eastern Ukraine, the U.N. chief said the need for a cease-fire is all the more urgent.

The onslaught and terrible toll on civilians we have seen so far could pale in comparison to the horror that lies ahead. This cannot be allowed to happen,”he told reporters, urging Russians and Ukrainians “to silence the guns and forge a path to safety for so many at immediate risk.”

He suggested the pause begin Thursday, which is Holy Thursday for Orthodox Christians, who make up the majority of Ukraine’s population.

Mr. Guterres said the goal is to open “ humanitarian corridors ” so civilians can escape embattled areas and more humanitarian convoys can get in, particularly to Donetsk, Luhansk and Mariupol in the eastern region known as the Donbas — the focus of Russia’s current offensive — and Kherson in the south. More than 4 million people in those areas, and 12 million nationwide, need food, water, medicine or other assistance.

Ukrainian Ambassador Mr. Sergiy Kyslytsya called on Russia to heed Mr. Guterres’ call. But Russian deputy Ambassador Mr. Dmitry Polyanskiy said Tuesday he was “a bit skeptical” about the idea.