Senior US officials are advising Ukraine to delay launching a major offensive against Russian forces until the country receives new weapons and Ukrainian soldiers are ready to use them, a senior Biden administration official said on Friday, according to Reuters.

The official, speaking to a small group of reporters on condition of anonymity, said the United States is sticking to its decision not to supply Abrams tanks to Ukraine at this time amid a dispute with Germany over the tanks.

U.S. negotiations with Ukraine about any counteroffensive were conducted to ensure the Ukrainians first had enough time to train with the latest weapons provided by the U.S., the official said.

The United States announced on Thursday that it will send hundreds of armored vehicles to Ukraine for use in combat operations.

Bad winter weather has “frozen” combat operations on the front line, although the cold air, which freezes and hardens the ground, can open the way for both sides to attack heavy equipment, said the governor of the Luhansk region Serhii Gaidai.

The official noted that the US currently does not plan to send Abrams tanks to Ukraine, as they are expensive and difficult to maintain.

German Defense Minister Boris Pistorius denied on Friday that Berlin was unilaterally blocking the delivery of Leopard main battle tanks to Ukraine, but said the government was ready to send them quickly if the allies reached a consensus.