Zelenskyy: Russian offensive in eastern Ukraine has begun

In this image from video provided by the Ukrainian Presidential Press Office, Ukrainian President Volodymyr Zelenskyy speaks from Kyiv, Ukraine, Monday, April 18, 2022. (Ukrainian Presidential Press Office via AP)

Burned vehicles are seen at the destroyed part of the Illich Iron & Steel Works Metallurgical Plant, as smoke rises from the Metallurgical Combine Azovstal during heavy fighting, in an area controlled by Russian-backed separatist forces in Mariupol, Ukraine, Monday, April 18, 2022. Mariupol, a strategic port on the Sea of Azov, has been besieged by Russian troops and forces from self-proclaimed separatist areas in eastern Ukraine for more than six weeks. (AP Photo/Alexei Alexandrov)

A man carries bicycle along a street filled with destroyed Russian military vehicles near Chernihiv, Ukraine, Sunday, April 17, 2022. Witnesses said multiple explosions believed to be caused by missiles struck the western Ukrainian city of Lviv early Monday as the country was bracing for an all-out Russian assault in the east. (AP Photo/Evgeniy Maloletka)

Servicemen of the Donetsk People's Republic militia look at bodies of Ukrainian soldiers placed in plastic bags in a tunnel, part of the Illich Iron & Steel Works Metallurgical Plant, the second largest metallurgical enterprise in Ukraine, in an area controlled by Russian-backed separatist forces in Mariupol, Ukraine, Monday, April 18, 2022. Mariupol, a strategic port on the Sea of Azov, has been besieged by Russian troops and forces from self-proclaimed separatist areas in eastern Ukraine for more than six weeks. (AP Photo/Alexei Alexandrov)

A man suspected to be a Russian collaborator is detained during an operation by Security Service of Ukraine (SBU) in Kharkiv, Ukraine, Monday, April 18, 2022. (AP Photo/Felipe Dana)

Valentyna Nechyporenko, 77, mourns at the grave of her 47-year-old son Ruslan, during his funeral at the cemetery in Bucha, on the outskirts of Kyiv, Monday, April 18, 2022. Ruslan was killed by Russian army on March 17 while delivering humanitarian aid to his neighbours in the streets of Bucha. (AP Photo/Emilio Morenatti)

Interior ministry sappers collect unexploded shell, grenades and other devices in Hostomel, close to Kyiv, Ukraine, Monday, April 18, 2022. (AP Photo/Efrem Lukatsky)

Russian military vehicles move on a highway in an area controlled by Russian-backed separatist forces near Mariupol, Ukraine, Monday. Mariupol, a strategic port on the Sea of Azov, has been besieged by Russian troops and forces from self-proclaimed separatist areas in eastern Ukraine for more than six weeks. (AP Photo/Alexei Alexandrov)

LVIV, Ukraine — Russia launched its long-feared, full-scale ground offensive to take control of Ukraine’s east on Monday, attacking along a broad front over 300 miles long, Ukrainian officials said in what marked the opening of a new and potentially climactic phase of the war.