South Korea, US wrap up annual military drills

South Korea and the United States on Friday wrapped up annual joint military exercises that always raise tensions with North Korea, which views them as provocative rehearsals for invasion.

Pyongyang conducted a series of short-range missile launches into the sea to register their displeasure with the joint drills, which began simultaneously on March 2.

The largely computer-simulated Key Resolve exercise ended March 13, but the large Foal Eagle drill -- involving 200,000 South Korean troops and 3,700 US troops -- lasted until Friday.

Both drills play out scenarios for a conflict with North Korea, but Seoul and Washington insist they are purely defensive in nature, despite Pyongyang's claims to the contrary.

Despite the missile tests -- one of which coincided with the arrival in the region of US Defence Secretary Ashton Carter for talks in Tokyo -- North Korea's reaction to the 2015 exercises was relatively restrained compared to some previous years when tensions have soared to dangerous heights.

South Korea's defence ministry has suggested the North might flex its military muscle with further tests or exercises on Saturday, the anniversary of the foundation of its armed forces.

Seoul's Yonhap news agency said North Korea had massed tanks and artillery units at a training field near Pyongyang.