North Korea on Tuesday issued a warning to the U.S. that it would unleash “merciless” attacks if an aircraft carrier strike group led by the USS Carl Vinson in the area infringes on its territory. “If they infringe on the DPRK’s sovereignty and dignity even a bit, its army will launch merciless ultra-precision strikes from ground, air, sea, and underwater,” said Pyongyang’s state-run news agency, KCNA. “On March 11 alone, many enemy carrier-based aircraft flew along a course near territorial air and waters of the DPRK to stage drills of dropping bombs and making surprise attacks on the ground targets of its army.” The Hermit Kingdom’s declaration came as the U.S. military announced it would permanently deploy missile-carrying Gray Eagle drones across the border in South Korea, escalating the confrontation and boosting “significant intelligence, surveillance, and reconnaissance capability” on the Korean Peninsula. Secretary of State Rex Tillerson arrives for his first official trip to the region on Wednesday. Officials from the U.S. Navy said the Carl Vinson is on a previously scheduled, routine deployment and that it will participate in exercises with South Korean forces despite any threats from North Korea.