The US decision to provide the advance rocket systems tries to strike a balance between the desire to help Ukraine battle ferocious Russian artillery barrages while not providing arms that could allow Ukraine to hit targets deep inside Russia and trigger an escalation in the war.

In a guest essay published Tuesday evening in The New York Times, Biden confirmed that he’s decided to “provide the Ukrainians with more advanced rocket systems and munitions that will enable them to more precisely strike key targets on the battlefield in Ukraine”.

Biden had said Monday that the US would not send Ukraine “rocket systems that can strike into Russia”. Any weapons system can shoot into Russia if it’s close enough to the border.

Biden added the US is not seeking a war between Nato and Russia. While he disagrees with Putin and is outraged by his actions, “the United States will not try to bring about his ouster in Moscow,” the US leader wrote.

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The aid package expected to be unveiled Wednesday would send what the US considers medium-range rockets – they generally can travel about 70km (45 miles), the officials said.

Ukraine has assured US officials that they will not fire rockets into Russian territory, according to the senior administration officials. One official noted that the advanced rocket systems will give Ukrainian forces greater precision in targeting Russian assets inside Ukraine.

The expectation is that Ukraine could use the rockets in the eastern Donbas region, where they could both intercept Russian artillery and take out Russian positions in towns where fighting is intense, such as Sievierodonetsk.

Sievierodonetsk is important to Russian efforts to capture the Donbas before more Western arms arrive to bolster Ukraine’s defence. The city, which is 145km south of the Russian border, is in an area that is the last pocket under Ukrainian government control in the Luhansk region of the Donbas.

It’s the 11th package approved so far, and will be the first to tap the US$40 billion in security and economic assistance recently passed by Congress. The rocket systems would be part of Pentagon drawdown authority, so would involve taking weapons from US inventory and getting them into Ukraine quickly. Ukrainian troops would also need training on the new systems, which could take at least a week or two.

Officials said the plan is to send Ukraine the High Mobility Artillery Rocket System, or Himars, which is mounted on a truck and can carry a container with six rockets. The system can launch a medium-range rocket, which is the current plan, but is also capable of firing a longer-range missile, the Army Tactical Missile System, which has a range of about 300km and is not part of the plan.

Since the war began in February, the US and its allies have tried to walk a narrow line: send Ukraine weapons needed to fight off Russia, but stop short of providing aid that will inflame Putin and trigger a broader conflict that could spill over into other parts of Europe.

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Over time, however, the US and allies have amped up the weaponry going into Ukraine, as the fight has shifted from Russia’s broader campaign to take the capital, Kyiv, and other areas, to more close-contact skirmishes for small pieces of land in the east and south.

To that end, Ukrainian President Volodymyr Zelensky has been pleading with the West to send multiple launch rocket systems to Ukraine as soon as possible to help stop Russia’s destruction of towns in the Donbas. The rockets have a longer range than the howitzer artillery systems that the US has provided Ukraine. They would allow Ukrainian forces to strike Russian troops from a distance outside the range of Russia’s artillery systems.

“We are fighting for Ukraine to be provided with all the weapons needed to change the nature of the fighting and start moving faster and more confidently toward the expulsion of the occupiers,” Zelensky said in a recent address.

Russia has been making incremental progress in the Donbas, as it tries to take the remaining sections of the region not already controlled by Russian-backed separatists.

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Russian Deputy Foreign Minister Sergei Ryabkov told state news agency RIA Novosti that Moscow views US military aid to Ukraine “extremely negatively” and would increase the risk of a direct confrontation.

Putin has repeatedly warned the West against sending greater firepower to Ukraine. The Kremlin said Putin held an 80-minute telephone call Saturday with the leaders of France and Germany in which he warned against the continued transfers of Western weapons.

Overall, the United States has committed approximately US$5 billion in security assistance to Ukraine since the beginning of the Biden administration, including approximately US$4.5 billion since the Russia invaded on February 24.

Associated Press, Agence France-Presse, Reuters and Bloomberg