WASHINGTON, April 25, 2024 (BSS/AFP) - The United States on Wednesday rushed to send ammunition, weapons and other war supplies to Ukraine, after President Joe Biden signed a much-delayed bill to support the country as it struggles to hold back Russian advances.

The final approval of the legislation -- which includes $61 billion for Kyiv out of a total of $95 billion in funding -- comes after months of political wrangling as Ukrainian forces ran short of ammunition and suffered battlefield setbacks.

"I just signed into law the national security package that was passed by the House of Representatives this weekend, and by the Senate yesterday," Biden told reporters, saying he is "making sure the shipments start right away, in the next few hours."

Minutes after Biden spoke, the Pentagon announced a $1 billion package for Kyiv using the new funding, including air defense munitions, artillery rounds, ammunition for HIMARS precision rocket launchers, anti-tank weapons and armored vehicles.

- 'Threats to freedom' -

Ukraine's President Volodymyr Zelensky quickly expressed thanks on social media.

"I am grateful to President Biden, Congress, and all Americans who recognize that we must cut the ground under Putin's feet rather than obeying him, as this is the only way to truly reduce threats to freedom," he wrote.

Washington has announced new aid for Ukraine on just one other occasion this year, a $300 million package in March that was only made possible by using money that the Pentagon had saved on other purchases.

The State Department confirmed Wednesday that the United States had secretly sent long-range ATACMS missiles to Ukraine as part of the March assistance package, fulfilling a long-standing request from Kyiv.

"We did not announce this at the onset in order to maintain operational security for Ukraine at their request," State Department spokesman Vedant Patel told reporters, adding that the "missiles arrived in Ukraine this month."

Some Army Tactical Missile System (ATACMS) missiles can hit targets up to 300 kilometers (190 miles) away, and a Defense Department spokesperson confirmed that was the long-range variant supplied to Ukraine.

The White House said last year that the United States sent a shorter-range variant of ATACMS that can travel 165 kilometers.

US National Security Advisor Jake Sullivan said the United States plans to send more of the long-range missiles to Ukraine, but warned that "there is no silver bullet."

The legislation Biden signed Wednesday passed after months of acrimonious debate among lawmakers over how or even whether to help Ukraine defend itself against Russia's invasion, which Moscow launched in February 2022.

A similar bill passed the Senate in February.

But it stalled in the House of Representatives while Republican Speaker Mike Johnson -- heeding calls from ex-president Donald Trump and his hardline allies -- demanded concessions from Biden on immigration policies, before Johnson made a sudden reversal.

- More Russian gains 'possible' -

The United States has been a key military backer of Ukraine, committing tens of billions of dollars in security assistance since the start of Russia's invasion.

But a squabbling Congress had not approved large-scale funding for Kyiv for nearly a year and a half.

Ukraine's military is facing a severe shortage of arms and recruits as Moscow exerts constant pressure from the east, and Sullivan said Wednesday that it is "certainly possible that Russia could make additional tactical gains in the coming weeks."

The bill signed by Biden also provides for much-needed humanitarian assistance to Sudan, Haiti and Gaza, with the president calling on Israel to allow aid to quickly reach Palestinians in the war-racked coastal enclave.

"We're going to immediately secure that aid and surge it... including food, medical supplies, clean water," Biden said. "Israel must make sure all this aid reaches the Palestinians in Gaza without delay."