North Korea fired two short-range missiles into the sea off its east coast on Monday, South Korea's military said, in a likely show of anger at the start of annual U.S.-South Korean military drills that Pyongyang says are preparation for a northward invasion.

North Korea regularly conducts such test firings of missiles, rockets and artillery, and they are often timed to express the country's dissatisfaction with actions by its archrivals, Washington and Seoul. Monday was the start of military drills that will run until the end of April.

Early Monday morning, two missiles launched from North Korea's west coast landed in waters off the east coast, a South Korean Defense Ministry official said, speaking on condition of anonymity, citing office rules.

The annual U.S.-South Korean military drills inevitably bring furious North Korean rhetoric, although the allies say they are purely defensive. The North's rhetoric is meant to show its people that a tough leadership is confronting what its propaganda portrays as outside hostility, but analysts also believe the drills infuriate because they cost Pyongyang precious resources by forcing the country to respond with its own drills and launches.

The rival Koreas earlier this year floated the possibility of holding what would be the third summit between their leaders since the countries were divided 70 years ago. But they have been at odds in recent weeks over terms, and prospects seem dim.

North Korea separately told the U.S. that it was willing to impose a temporary moratorium on its nuclear tests if Washington cancels the joint military drills with South Korea. But the U.S. rejected the overture, calling it an "implicit threat."

North Korea last year conducted an unusually large number of missile and other weapons tests, drawing protests from South Korea. The North still proposed a set of measures that it said would lower tensions, but South Korea rebuffed them, saying the North must first take steps toward nuclear disarmament.

The Korean Peninsula remains in a technical state of war because the 1950-53 Korean War ended with an armistice, not a peace treaty.