A NASAMS surface-to-air missile launcher -- a system that Ukraine's supporters have provided to Kyiv -- is seen during production in Kongsberg, Norway on January 30, 2023
A NASAMS surface-to-air missile launcher -- a system that Ukraine's supporters have provided to Kyiv -- is seen during production in Kongsberg, Norway on January 30, 2023 AFP

The United States on Tuesday announced a new $1.2 billion security assistance package for Ukraine to boost the country's air defenses and provide it with additional artillery ammunition.

Ukraine is readying for a highly anticipated spring offensive against invading Russian troops, but the latest assistance will not immediately arrive on the battlefield as it must still be procured from the defense industry or partners.

This avoids depleting US stocks, but means the assistance will take longer to reach Kyiv than equipment drawn directly from existing American military inventories.

The package underscores the continued US commitment to Ukraine "by committing critical near-term capabilities, such as air defense systems and munitions, while also building the capacity of Ukraine's armed forces to defend its territory and deter Russian aggression over the long term," the Defense Department said in a statement.

Ukrainian President Volodymyr Zelensky hailed the new assistance, saying on Twitter that "we appreciate this sign of solidarity with Ukraine shown on a symbolic day for us -- Europe Day and the Day of Victory over Nazism in WWII."

"Together we're moving towards a new victory!" he added.

The package features unspecified air defense systems and munitions as well as equipment to integrate Western systems with Ukraine's existing gear, which is mainly of Soviet vintage.

Pentagon spokesman Brigadier General Pat Ryder told journalists Tuesday that the specific air defense systems have not yet been selected, saying the announcement represents "the beginning of a contracting process to provide additional priority capabilities to Ukraine."

Ukraine's air defenses have played a key role in countering Russia's invasion, preventing Moscow's forces from gaining control of the skies and helping shield the country against missile and drone attacks.

Secret US documents from late February that were allegedly leaked online by a junior member of the Air National Guard detailed looming munitions shortages for Soviet systems that make up a significant chunk of Ukrainian medium and high-range protection.

Kyiv's international supporters have worked to bolster its existing defenses with a mix of cutting edge systems such as Patriot and NASAMS, as well as older equipment.

Ryder confirmed that a Patriot battery had shot down a Russian hypersonic Kinzhal missile, which Ukraine had previously said took place during a wave of attacks by Moscow's forces last week.

The assistance package also includes ammunition for counter-drone systems meant to foil the threat of Iranian-made uncrewed aircraft that Russia has used for strikes in Ukraine, as well as 155 mm rounds -- a key type of artillery ammunition for Ukraine's forces.

It will also provide commercial satellite imagery services as well as support for training and maintenance.

The latest assistance brings total US military aid to Ukraine since Russia invaded the country in February 2022 to more than $36 billion.

The United States has spearheaded the push for international support for Ukraine, quickly forging an international coalition to back Kyiv after Russia invaded in February 2022 and coordinating aid from dozens of countries.

US Secretary of State Antony Blinken said at a news conference alongside his British counterpart on Tuesday that Ukraine has what it takes to "continue to be successful in regaining territory that was seized by force by Russia over the last 14 months."