US media are reporting that a senior US military official has said Ukraine could suffer a significant setback or even defeat by next summer if it does not receive more aid from the United States and other countries.

CNN reported on Friday that Western intelligence agencies are calculating how long Ukraine could hold out without US and NATO help.

It says officials assess that without additional US aid, Ukraine would first run out of long-range missiles, then air defense missiles, followed by artillery ammunition and short-range missiles such as shoulder-fired Javelin anti-tank missiles.

The network quoted US and Ukrainian officials as saying that Ukraine's forces are already rationing ammunition as Russian forces return fire at a ratio of five to seven times greater than Ukrainians.

A senior Ukrainian military official is quoted as saying the impact on their firepower has led to additional causalities.

Attention is now focused on whether Ukraine will be able to receive more support from Western countries. Some Republican members of the US Congress are reluctant to continue providing aid to Ukraine.