A Ukrainian general confirmed to CNN on Thursday that Ukraine had received the cluster munitions from the US, nearly a week after President Joe Biden said he had made the “difficult decision” to approve their transfer to Ukraine.

“We just got them, we haven’t used them yet, but they can fundamentally change the battlefield,” Brigadier General Oleksandr Tarnavskiy, commander of Joint Forces Operation Tavria, told CNN’s Alex Marquardt in an interview Thursday.

“The enemy also understands that by acquiring these munitions, we will have an advantage. The enemy will leave areas where they can be used,” he said.

It is the first time it is reported that Ukraine has already received the cluster weapons. Senior leadership will decide on the “territory areas where they can be used,” Tarnawski said, noting that “this is a very powerful weapon.” “The Russians believe that we will use it in all areas of the front,” he added. “This is very wrong. But they are very worried.”

Tarnavski stressed the limitations on the use of cluster munitions, saying their use is prohibited in populated areas, even if they are occupied by Russian forces. The US said it had written assurances from Ukraine that they would not be used in civilian areas and that their use would be monitored for possible demining operations.

The US said the decision to provide Ukraine with cluster munitions was due to Kiev’s lack of standard artillery shells. The supply of cluster munitions is “temporary,” according to US National Security Adviser Jake Sullivan.

“Once production reaches a level where it can meet Ukraine’s needs, then there will be no need to continue giving cluster munitions,” he said on Tuesday, declining to give a timetable.