Ukraine says shortage of weapons are causing difficulties on the battlefield. Here's what to know

As the future of the United States' congressionally-approved assistance for Ukraine remains in question, Ukrainian President Volodymyr Zelensky said Kyiv "will do everything" to maintain support from the US and Europe in its fight against Russia's full-scale invasion.

Meantime, allies are warning they are running low on ammunition and are ramping up production — the same shortages Zelensky says are creating challenges on the battlefield.

Here's the latest:

• US aid concerns: The ousting of US House Speaker Kevin McCarthy has cast fresh doubt on the future of American aid for Ukraine. President Joe Biden said Wednesday he is concerned as he works to secure new funding, but he argued that it remains in Americans' interest to continue supporting Ukraine. The leading contenders vying for the speakership have voiced different positions on Ukraine. 
• Zelensky rallies support: The Ukrainian president said he believes Russia is now weaker than it was at the beginning of the war, so pausing the support or turning the fighting into a frozen conflict  would mean helping the aggressor. His comments come in the context of disarray within the Republican ranks on Capitol Hill. Zelensky reiterated that "for the most part" there is bipartisan support for Ukraine.
• Weapons challenges: Ukraine is "slowly but surely" pushing Russia out of its land, but weapons and ammunition shortages pose difficulties, Zelensky said. Western militaries said they are running out of ammunition to give to Ukraine, NATO and UK officials warned Tuesday. The Pentagon has also warned about depleting funds.
• Iranian arms: The US said it will transfer thousands of seized Iranian weapons and ammunition rounds to Ukraine, which could help to alleviate some of the critical shortages. The Biden administration has for months been weighing how to legally send the seized weapons, which are stored in US facilities across the Middle East.
• NATO backing: NATO is reaffirming its long-term support to Kyiv after a meeting of the new defense council between the military alliance and Ukraine. A statement said allies will continue to assist and that Ukraine is "closer to NATO than ever before."  
• Southern battles: Both Russian and Ukrainian units are trying to take territory around the southern villages of Verbove and Novoprokovika, Ukrainian military officials say. Ukraine has had "partial success" in Robotyne in the Zaporizhzhia region, according to Oleksandr Shtupun, spokesperson for Ukraine's forces in the south. Though progress has been slow, Russian forces are suffering losses of manpower and equipment there, Shtupun said.
• Cross-border attacks: Drones operated by Ukraine's Security Service successfully took out a high-value Russian air defense complex in the region of Belgorod early Wednesday, sources say. Belgorod borders northeastern Ukraine. Last month, Ukraine successfully targeted an air defense complex in Crimea.