JERUSALEM — Civil-defense sirens sounded at 8 p.m. to mark the start of Israel’s solemn Memorial Day observance, but unlike in ordinary years, when the moment is marked by a sudden halt to traffic and an abrupt quieting of nightlife, Monday night’s remembrance of fallen soldiers or victims of terrorism came with most of the country already on lockdown.

At the Western Wall in Jerusalem, Israel’s president, Reuven Rivlin, spoke before a small coterie of socially distanced troops and officials and sought to console those Israelis who were mourning alone, at home, rather than being “wrapped in the embrace of those who love them.”

Graveside gatherings on Memorial Day are a binding ritual in a country where wars and conflict have touched nearly everyone, but Israel’s cemeteries were ordered closed to avoid crowds and prevent the spread of the coronavirus. “Every Israeli home will be a memorial this year,” Mr. Rivlin said, adding: “We will embrace you, beloved families, from afar, our hearts with yours.”

The coronavirus was a boon, however, to an alternative ceremony that for 15 years has drawn together bereaved families from both sides of the Israeli-Palestinian conflict.