Grain silos in Ukraine’s second biggest port, Mykolaiv, were hit by Russian shelling of the city on Tuesday, causing a fire that was still burning on Wednesday, Ukraine’s emergencies service said.

“As a result of the shelling of Mykolaiv, grain silos at an infrastructure facility in the Korabelny district caught fire,” the emergencies service said on Facebook on Wednesday. “Firefighting continues.”

It published photos showing holes in the metal roofs of at least two silos and fire brigades pouring water on damaged facilities. A 200 square metre area had been affected, it said, without giving any further details.

There are several major grain terminals in Mykolaiv, and some have already come under attack during the Russian invasion, which Moscow calls a “special military operation”.

Ukraine is conducting a counter-offensive in the area, which has come under constant shelling in recent weeks, to try to push Russian troops out of the city of Kherson to the southeast and drive them back towards Crimea, which Russia annexed in 2014.

Ukraine’s grain exports slumped after Russia invaded the country on Feb. 24 and blockaded its Black Sea ports, driving up global food prices and prompting fears of shortages in Africa and the Middle East.