The Kremlin said Monday it may still opt to take control of large cities in Ukraine, as Moscow's military advances steadily towards several major urban hubs in its pro-Western neighbor.

"Putin gave orders to hold back on any immediate assault on large cities because the civilian losses would be large," Kremlin spokesman Dmitry Peskov told reporters.

He added however that the defence ministry "does not rule out the possibility of putting large cities, which are already almost fully encircled, under its full control".

Exceptions would be made for areas "used for humanitarian evacuations," Peskov said.

"US and EU leaders it seems are forcing Russia towards an assault of large Ukrainian cities to hold our country responsible for civilian deaths," he added.

Peskov also denied reports Russia has asked China for military aid.

"Russia has its own potential to continue the operation," Peskov told reporters.