WASHINGTON, Oct 8 (AFP) - The United States will soon be unable to provide Ukraine with certain types of ammunition that are essential to Kyiv's battle against Russia's invasion, as supplies are being used up faster than they can be replaced.

Washington has become by far the largest supplier of arms to Ukraine since Russia launched the invasion on Feb 24, with more than US$16.8 billion in military assistance provided.

But US stockpiles of some equipment are "reaching the minimum levels needed for war plans and training", and restocking to pre-invasion levels could take years, Mark Cancian of the Center for Strategic and International Studies wrote in a recent analysis.

Washington is "learning lessons" from the conflict about ammunition needs in a great power war, which are "far greater" than expected, a US military official acknowledged on condition of anonymity.

American defence firms were forced to drastically reduce production in the 1990s as the United States slashed defence spending following the collapse of the Soviet Union, and their number fell dramatically, from dozens to single digits.

Now, the US government must convince the industry to reopen assembly lines and relaunch production of items such as Stinger anti-aircraft missiles, which have not been made since 2020.

Some US-provided equipment has become emblematic of the war in Ukraine, such as Javelin anti-tank weapons that were widely used by Kyiv's forces to blunt the Russian advance on the capital, and the Himars, a precision rocket system now playing a key role in counter-offensives against Moscow's troops in the east and south.