It comes amid anger in Pyongyang at ongoing US-led military exercises with South Korea – which the North views as a rehearsal for invasion.
And there is growing frustration in Kim Jong-un’s regime at stalled talks between the US and North Korea over his weapons programme.
The unidentified projectiles smashed into waters off North Korea’s eastern coast on Friday morning local time, South Korea’s military said.
They are likely to be the same short range rockets used in recent launches – which despot Kim had said would cause “inescapable distress to a fat target.”
‘GUIDED ROCKET SYSTEM’
North Korean state media previously described the weapon as a “new-type large-calibre multiple launch guided rocket system” – but no specific details were given.
The launch came after the North issued a statement berating South Korea – saying it’s “senseless” to resume peace talks while the joint-US military drills continue.
It extends a recent streak of rocket tests believed to be aimed at pressuring Washington and Seoul over slow nuclear diplomacy.
The US is trying to get North Korea to rein in its nuclear weapons arsenal and curb long-range missile tests.
But North Korea is angling for crippling economic sanctions imposed on it to be lifted first.
President Donald Trump has repeatedly played down the rocket launches – which some experts fear may be encouraging Pyongyang to act recklessly.