Ukraine would welcome receiving cluster munitions from the United States because they would have an "extraordinary psycho-emotional impact" on Russian forces, a senior Ukrainian official said on Friday.

Three U.S officials speaking on condition of anonymity this week said a weapons aid package that includes cluster munitions fired by a 155 millimeter Howitzer cannon was expected to be announced as soon as Friday.

Such a move is opposed by human rights groups but could provide a powerful new element to a counteroffensive against Russian forces fighting in Ukraine.

"Undoubtedly, the transfer of additional volumes of shells to Ukraine is a very significant contribution to the acceleration of de-occupation procedures," presidential political adviser Mykhailo Podolyak told Reuters.

"Especially if we are talking about cluster ammunition, which is undoubtedly capable of having an extraordinary psycho-emotional impact on already demoralized Russian occupation groups."

He said a decline in the combat capacity and morale of Russian soldiers was "an important component that can be provided by this type of projectile."

Ukraine needed more shells and ammunition and was grateful to its partners for "understanding the harsh realities of war," Podolyak said.

The White House said on Thursday that sending cluster munitions to Ukraine was "under active consideration" but that it had no announcement to make.

Human Rights Watch has called on Russia and Ukraine to stop using cluster munitions and urged the U.S. not to supply them. The group said that both Russian and Ukrainian forces have used the weapons, which have killed Ukrainian civilians.

The munitions, banned by over 120 countries, typically release large numbers of smaller bomblets that can kill indiscriminately over a wide area.