North Korea on Friday test-fired four missiles off its west coast, a week ahead of a visit to Seoul by the U.S. defense secretary, in what South Korea called a bid to stoke tension during its joint military drills with the United States.
North Korea occasionally fires short-range missiles into the sea as part of its military drills and has conducted such launches during times of tension with neighboring South Korea.
The four short-range projectiles flew roughly 140 km (84 miles) and plunged into the sea late on Friday afternoon, South Korea's office of the Joint Chiefs of Staff said.
"The projectiles are believed to be for a provocative show of force to pressure the South," the office said in a statement, adding that the North had fired a similar object on Thursday.
Since March 2, South Korea and U.S. forces have been conducting annual joint military drills that are set to end on April 24. North Korea harshly criticizes the drills, calling them a prelude to war.
Friday's firings come ahead of U.S. Defense Secretary Ashton Carter's three-day visit to South Korea, starting from Thursday, to discuss the allies' defense against the North's missile and nuclear capabilities.
The North has a stockpile of ballistic missiles and successfully launched a long-range rocket in 2012 that is believed to have put an object into space orbit.
The 2012 launch was conducted from a missile site near the west coast, from where Friday's firings are believed to have been held.