SEOUL (AFP) - North Korea test-fired two short-range missiles into the sea off its eastern coast on Monday, the second in a series of launches that Seoul has denounced as a calculated provocation.
"Both missiles flew more than 500 kilometres," a South Korean defence ministry spokesman told AFP.
The range would suggest they were the same as the four Scud missiles the North fired in similar fashion on Thursday - just days after South Korea and the United States launched annual joint military exercises.
The Scuds are at the longer edge of the short-range spectrum, with an estimated reach of 300-800 kilometres - capable of striking any target in the South.
It is not unusual for North Korea to carry out such tests - especially to register its displeasure at the annual military drills - and they often go unreported by South Korea.
Washington had initially played down Thursday's firings, but later suggested they violated UN sanctions imposed on the North's missile programme.
UN Security Council resolutions prohibit North Korea "from launching any ballistic missile, and this includes any Scud missile", Pentagon spokesman Colonel Steven Warren said on Friday.
The South's defence ministry had called last week's tests a "calculated, provocative act." But they are unlikely to trigger a significant rise in military tensions, with observers suggesting they amount to little more than a display of North Korean frustration over the annual drills in the South.
Pyongyang routinely condemns the joint exercises, which began last week and run until mid-April, as provocative rehearsals for invasion.
Last year, they coincided with a sharp and unusually protracted surge in cross-border tensions that saw North Korea issuing apocalyptic threats of pre-emptive nuclear strikes.
By contrast, this year's drills began as relations between Seoul and Pyongyang were enjoying something of a thaw.
They overlapped with the end of the first reunion for more than three years of families divided by the Korean War - an event that raised hopes of greater cross-border cooperation.
Pyongyang had initially insisted that the joint exercises be postponed until after the reunions finished. But Seoul refused and - in a rare concession - the North allowed the family gatherings on its territory to go ahead as scheduled.
Most analysts believe the missile tests reflect Pyongyang's need to flex its muscles in the wake of the reunion compromise.
Last week also saw an incursion by a North Korean patrol boat across the disputed Yellow Sea border that has been the scene of brief but bloody naval clashes in the past.
No shots were fired and the vessel retreated to its side of the boundary after repeated warnings from the South Korean navy.
North Korea has hundreds of short-range missiles and has developed and tested - with limited success - several intermediate-range models.
Its claims to have a working inter-continental ballistic missile have been treated with scepticism by most experts, but there is no doubt that it is pushing ahead with an active, ambitious missile development programme.