“I’ve decided that we will 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 wrote in a New York Times article published on Tuesday evening in Washington.

The package of weapons includes missiles that will allow Ukraine to strike locations as far as 80km away, a senior US official told reporters on condition of anonymity. World leaders including British Prime Minister Boris Johnson have publicly called for such a move in recent weeks.

The decision comes more than three months after President Vladimir Putin’s forces invaded Ukraine, with the conflict now shifting into a brutal town-by-town grind as Russia tries to consolidate territory in the east rather than seize control of the entire country. That change in strategic goals has altered how the war is waged, with longer-range bombardment including by artillery increasingly a part of the fighting.

One concern in Washington and some European capitals about supplying longer-range weaponry and munitions was whether Ukraine would use them to strike targets inside Russia. That would risk expanding the war and pulling in NATO nations that have sought to draw a line between delivering defensive aid and engaging more aggressively in the conflict.

The US official said Ukraine’s government offered assurances that they won’t use the new missile systems to target Russian territory. In its latest tranche, the US stopped short of agreeing to send the longest-range munitions while highlighting previous shipments of other advanced systems, including howitzers and antitank weapons.

The White House plans to announce the new $700-million security assistance package on Wednesday, US officials said. Since the war began, the US has supplied more than $4.5-billion in military aid.

Read more: Russian Wins in Eastern Ukraine Spark Debate Over Course of War

Biden administration officials have vowed to weaken Russia so that it can’t again attack a neighbor, imposing a slew of sanctions on Moscow and bolstering Ukraine’s military with billions of dollars in arms. But the goal of evicting Russian forces from Ukraine seems more distant, even after President Volodymyr Zelenskiy’s military forced Moscow to scale back its early ambitions to capture Kyiv and quickly replace the government.

“If Russia does not pay a heavy price for its actions, it will send a message to other would-be aggressors that they too can seize territory and subjugate other countries,” Biden wrote. “It could mark the end of the rules-based international order and open the door to aggression elsewhere, with catastrophic consequences the world over.” BM