President Joe Biden on Tuesday confirmed the United States will send more advanced rocket systems to Ukraine with ability to strike what he called "key targets" of Russia's invasion force."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 The New York Times.A U.S.

official told reporters that the weapons being sent are Himars, or the High Mobility Artillery Rocket System.With precision-guided munitions and a longer range than weapons currently deployed by Ukraine, the multiple rocket launchers represent an important upgrade at a time when the Ukrainians are battling Russian artillery in the east of the country.The Himars rockets "will enable the Ukrainians to more precisely strike targets on the battlefield from greater distance inside Ukraine and to help them repel Russia," the official said, speaking on condition of anonymity."These systems will be used by the Ukrainians to repel Russian advances on Ukrainian territory but they will not be used against Russia."The Himars are the centerpiece of a $700 million package being unveiled Wednesday, also including air surveillance radars, more Javelin short-range anti-tank rockets, more artillery ammunition, helicopters, vehicles and spare parts, the official said.Although there'd been speculation for days that Himars were going — following repeated pleas from Ukraine's outgunned military — the announcement also made clear the U.S.

attempt to help Kyiv's war effort while not being seen as a direct belligerent.For that reason, the ammunition for the Himars will not include a version able to reach some 186 miles (300 kilometers), out of fear that the Ukrainians would use it to hit deep inside Russia.They will instead get the version extending about 50 miles (80 km), which is still significantly further than the Ukrainians' present capabilities, the U.S.

official said.

That means Ukraine's forces will be able to strike at Russian positions with the rockets from relative safety.The "Ukrainians have given assurances they will not use these systems against Russian territory," the official stressed.The new weaponry will come from a recently approved fund of $40 billion.

Already the Biden administration has sent $4.5 billion in mostly military aid to Ukraine since the war began with Russia's February invasion.Asked what the United States considers the war aim for Ukraine, the official said it was to put Kyiv "in the strongest possible position at the negotiating table."While the United States does not want to "prolong the war," it considers it vital that Russia "pay a heavy price for its actions" or it will "send a message to other would-be aggressors that they can take a territory by force," the official said."We will not pressure the Ukrainian government in private or in public to make any territorial concessions," the official said.