KYIV, Ukraine — A major Russian drone and missile attack on civilian areas of Ukraine killed six people and injured at least 46, officials said Tuesday, while Moscow’s army stepped up efforts to break through Ukrainian front-line defenses in what could be the start of an anticipated spring ground offensive.

Russia fired almost 400 long-range drones at Ukraine overnight, Ukraine’s air force said, in its biggest attack in weeks. The onslaught continued into Tuesday as dozens of drones targeted the capital Kyiv during daylight.

Russia launched swarms of Iranian-designed Shahed drones, hitting at least seven cities, Ukrainian Foreign Minister Andrii Sybiha said on X.

Russia also launched 23 cruise missiles and seven ballistic missiles at Ukraine during the night, hitting at least 10 locations across the country, according to the air force. Daytime strikes injured 13 people, including three children, in the central Ukraine city of Dnipro, and another daylight attack hit an apartment block in the center of the western city of Lviv, near the Polish border, where 13 people were injured, regional officials said.

The Lviv attack set fire to the city’s 17th-century St. Andrew’s Church, which is part of a UNESCO World Heritage site, Prime Minister Yulia Svyrydenko said.

In the central city of Ivano-Frankivsk, the attack damaged maternity hospitals and about 10 apartment buildings, according to Svitlana Onyshchuk, the head of the regional military administration. Two people were killed and four injured, including a 6-year-old child, she said.

Ukrainian civilians have endured relentless barrages since Russia launched a full-scale invasion of its neighbor more than four years ago. U.S.-brokered talks between Moscow and Kyiv over the past year have brought no respite, with Russia rejecting Ukraine’s offer of a ceasefire, and in recent weeks the Iran war has diverted international attention from Ukraine’s plight.

On the roughly 750-mile front line snaking along eastern and southern parts of Ukraine, the short-handed defenders have been bracing for a new offensive by Russia’s bigger army as the weather improves.