Ukraine was fully within its rights to launch its surprise offensive into Russia’s Kursk border region as an act of self-defense, NATO chief Jens Stoltenberg told German newspaper Die Welt. The offensive launched on Aug. 6 caught the Kremlin off guard, with Kyiv claiming to have captured dozens of settlements and more than 1,200 square kilometers (nearly 500 square miles) of territory. “Ukraine has a right to defend itself. And according to international law, this right does not stop at the border,” Stoltenberg said in an interview with Die Welt published Saturday. “The Russian soldiers, tanks…