UNITED NATIONS — U.N. Secretary-General Antonio Guterres called Tuesday for a four-day “humanitarian pause” in fighting in Ukraine, starting Thursday to coincide with Orthodox Christians’ Holy Week observances.

Noting that the Easter season is coming amid an intensifying Russian offensive in eastern Ukraine, the U.N. chief said the need for a “humanitarian pause” 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.”

Guterres said the proposed pause would allow for evacuating civilians from “current or expected areas of confrontation” and getting more humanitarian aid into desperately needy places such as Mariupol, Donetsk, Luhansk and Kherson. More than four million people in those areas need assistance, Guterres said.

His remarks came a day after U.N. humanitarian chief Martin Griffiths suggested “maybe there will be some ripeness” for a cease-fire as the Orthodox Easter holiday approaches. Griffiths had traveled to Ukraine and Russia earlier this month to try to gauge the potential for a cease-fire and emerged saying he wasn’t optimistic at the time.

Griffiths on Tuesday broached the idea of a Holy Week pause with the Ukrainian Council of Churches and Religious Organizations, an interfaith group, Guterres said.

“The four-day Easter period should be a moment to unite around saving lives and furthering dialogue to end the suffering in Ukraine,” Guterres said.

The proposal comes after the U.N. recently helped to foster a two-month truce in Yemen’s civil war, halting fighting as the Muslim holy month of Ramadan began.