North Korea fired two short-range ballistic missiles into the sea Monday from an airport in capital Pyongyang, South Korea and Japan said. China did not confirm the launch but a foreign ministry spokesperson said: “We call on relevant sides to keep in mind the overall peace and stability on the peninsula.” The test is the fourth this month alone and will fuel fears about the increasing size and capability of the nuclear-armed country’s arsenal. Japan said the pair of missiles appeared to have landed in the ocean off North Korea’s east coast, with its foreign minister saying: “The repeated launching of North Korea’s ballistic missiles is a grave problem for the international community, including Japan.” A U.S. Army spokesperson told Reuters: “These missile launches highlight the destabilizing impact of [North Korea’s] illicit weapons program.” North Korea has defended the current run of missile tests, saying it has a right to self-defense and accused the U.S. of “isolating and stifling” the country.