The U.S. military sent a nuclear-capable B-2 stealth bomber from Whiteman Air Force Base in Missouri on a long-range mission to the Pacific area of operations over the weekend, it said Sunday, a day after Pentagon chief Jim Mattis highlighted rival North Korea's "accelerating" atomic weapons program during a visit to South Korea.

The U.S. military's Strategic Command said in a statement that the type of long-range mission conducted was to "familiarize aircrew with air bases and operations in different geographic combatant commands, enabling them to maintain a high state of readiness and proficiency."

In a message likely intended to reassure Japan and South Korea ahead of U.S. President Donald Trump's visit to Asia, which kicks off later this week, the statement also referred to the B-2 mission as "a visible demonstration of commitment to our allies and enhancing regional security."