Russia launched missile strikes across Ukraine on Thursday, Ukrainian officials said, after Western allies pledged to ramp up military aid to the Ukrainian armed forces to support a planned counter-offensive.

Ukrainian officials said air defences in the south downed eight Kalibr missiles fired from a ship in the Black Sea, but other missiles struck northern and western Ukraine as well as the central regions of Dnipropetrovsk and Kirovograd.

One missile struck an industrial site in the western city of Lviv, causing a fire which was brought under control, authorities said.

Bolstered by tens of thousands of reservists drafted in December, Russia has intensified ground attacks across southern and eastern Ukraine in recent weeks, and a major new offensive is widely expected as the first anniversary of its Feb. 24 invasion nears.

“The enemy’s offensive continues in the east, (with) round-the-clock attacks,” Ukrainian Deputy Defence Minister Hanna Malyar said on Wednesday.

“The situation is tense. But our fighters are not allowing the enemy to achieve their goals and are inflicting very serious losses,” she wrote on the Telegram messaging app.

The Russian Defence Ministry earlier on Wednesday said Ukrainian forces had retreated in the face of Russian operations in the Luhansk region, although it gave no details and Reuters was not able to verify this and other battlefield reports.

“During the offensive... the Ukrainian troops randomly retreated to a distance of up to 3 km (2 miles) from the previously occupied lines,” the ministry said on Telegram.

The ministry did not specify in which part of Luhansk the offensive took place. The Luhansk and Donetsk regions make up the Donbas, Ukraine’s industrial heartland, now partially occupied by Russia which wants full control.

In Kyiv, the capital’s military administration said six Russian balloons that may have contained reconnaissance equipment were shot down after air raid sirens blared.

Russia did not immediately comment.

Russia’s main effort has been an artillery and ground onslaught on the city of Bakhmut, in Donetsk.

Ukrainian military analysts said Russian troops had launched several unsuccessful attacks on villages to the north and south of Bakhmut over the past day.

“Things are very difficult for our forces there as Russian troops are being sent into the area en masse,” analyst Oleh Zhdanov said.

The General Staff of the Ukrainian Armed Forces, in its evening report, said Russian forces had fired on more than 15 towns and villages near Bakhmut, including the city itself.

Donetsk regional Governor Pavlo Kyrylenko posted pictures and video of an apartment building littered with rubble that he said was destroyed in the city of Pokrovsk, southwest of Bakhmut, killing three people.

Bakhmut’s capture would give Russia a stepping stone to advance on two bigger cities, Kramatorsk and Sloviansk further west in Donetsk, which would revive Moscow’s momentum ahead of the February 24 anniversary of the invasion.