The U.S. will supply Ukraine with further munitions for long range weapons that are effectively targeting Russian forces as part of a bumper security package, according to a report.

Reuters said President Joe Biden's administration is set to announce a $1 billion package which includes munitions for the U.S.-produced M142 High Mobility Artillery Rocket Systems (HIMARS), whose range have allowed Kyiv to hit significant targets.

There are reportedly 16 U.S.-supplied HIMARS in Ukraine which Kyiv's forces say have successfully hit Russian command centers and ammunition depots.

The new package will come via the Presidential Drawdown Authority (PDA), which allows Biden to authorize transfers from U.S. stocks without the approval of Congress.

US military personnel stand by a M142 High Mobility Artillery Rocket System (HIMARS) in Riyadh during Saudi Arabia's first World Defense Show on March 6, 2022. Reuters reported on 5 August, 2022 that the U.S. is set to supply Kyiv's forces with munitions for the weapons which have successfully struck Russian targets. Getty Images

Also in the package will be NASAMS surface-to-air missile system ammunition and up to 50 M113 armored medical transport vehicles, 200 of which the U.S. had previously committed to Ukraine.

In July, the U.S. pledged to send two NASAMS, although it is unclear if the launchers are already in Ukraine, or if the munitions were for launchers donated by another country.

The latest U.S. contribution, which could be announced as early as Monday, adds to the $8.8 billion in American aid to Kyiv since the start of the war on February 24.

Newsweek has contacted the Pentagon for comment.

Ukraine has praised the latest delivery of HIMARS and Ukrainian President Volodymyr Zelensky hailed the amount of support his forces are receiving from the U.S., saying that it "is bringing us closer to victory."

And the Financial Times reported that the HIMARS systems were "fueling Ukraine's hopes" of a counter-offensive.

It comes as the British Ministry of Defense said on Saturday that Russia's war on Ukraine "is about to enter a new phase."

In its daily assessment, defense officials said Russian convoys of military vehicles and weapons were moving away from the eastern Donbas region and massing in the south in anticipation of a "possible assault" or a counter-offensive by Kyiv.

They said that equipment was also moving from Russian-occupied Melitopol, Berdiansk, Mariupol and from mainland Russia via the Kerch Bridge into Crimea, which Russia annexed in 2014.

Battalion tactical groups (BTG) of up to 1,000 troops had been deployed to Crimea "and would almost certainly be used to support Russian troops in the Kherson region," which Ukraine is trying to wrest from Russian control.

Meanwhile, Ukrainian forces were continuing to target bridges, ammunition depots, and rail links in the southern regions.

This push includes the strategically important railroad spur that links Kherson to Crimea, as Ukraine tries "to affect Russia's ability to logistically resupply."

Last week, Ukrainian forces used HIMARS to hit Antonivskiy Bridge and a nearby rail bridge over the Dnipro River in Kherson, dealing Russian forces a blow.

Newsweek has contacted the defense ministries of Ukraine and Russia for comment.