The Pentagon has indicated that the lack of funding not only affects the US's ability to send weapons to Ukraine but also to help repair the equipment it has already provided.

The official stressed that due to insufficient funding, the Pentagon cannot draw down weapons from its own stockpiles, which hinders "meeting Ukraine's most urgent battlefield needs to include things like artillery rounds, anti-tank weapons, air defence interceptors," Patrick Ryder, spokesperson for the US Department of Defense, said during a briefing.

"Also, without additional funding, it prevents us from being able to provide systems and equipment to meet both their medium- and longer-term requirements and help them sustain systems that we've previously provided to them," Ryder stressed.

The official added that the Pentagon would further cooperate with Congress and urge it to pass a decision on additional funding as soon as possible.

Earlier, the White House stressed the importance of making a decision on assistance to Ukraine as soon as possible, as the next few months will be critical.

Media reports indicated that key aides to US President Joe Biden warned at a closed-door meeting in Congress that without approval of additional military aid to Ukraine, significant challenges could arise on the battlefield.

The bill envisages over US$60 billion in support for Ukraine, US$14 billion for Israel, and the same amount for measures to counter illegal migration on the southern border.

The White House has previously stated that it no longer has money for new military support for Ukraine until it is approved by the US Congress.