Flush with success in northeast Ukraine, President Volodymyr Zelenskyy is pressing U.S. President Joe Biden for a new and more powerful weapon: a missile system with a range of 190 miles (305 kilometers), which could reach far into Russian territory.

Zelenskyy insists to U.S. officials that he has no intention of striking Russian cities or aiming at civilian targets, even though President Vladimir Putin’s forces have hit apartment blocks, theaters and hospitals in Ukraine throughout the war. The weapon, Zelenskyy says, is critical to launching a wider counteroffensive, perhaps early next year.

Biden is resisting, in part because he is convinced that over the past seven months, he has successfully signaled to Putin that he does not want a broader war with the Russians — he just wants them to get out of Ukraine.