WASHINGTON (AP) — The Biden administration is sending Ukraine a small number of high-tech, medium-range rocket systems. Ukrainian leaders have been begging for the critical weapons as they struggle to stall Russian progress in the Donbas region. The U.S. plan 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. In an essay for The New York Times, Biden says the administration is not encouraging or enabling Ukraine to strike beyond its borders. The rocket systems are part of a new $700 million tranche of security assistance from the U.S.