Shinzo Abe, the Japanese prime minister, who usually takes a hardline on North Korea, downplayed the significance of the missiles.
"I do not consider it as a grave issue for Japan's security," Abe told reporters, adding that he wanted North Korea to adhere to the six-party agreement.
North Korea's missile development and its pursuit of nuclear weapons have been a growing cause of concern among its neighbours, but under a deal agreed at six-party talks in Beijing in February, North Korea agreed to begin shutting down its nuclear programme by April 17.
Noriyuki Shikata, a spokesman for Japan's foreign ministry, told Al Jazeera: "It's a bit premature to make a link between these reports [of the missile launch] and the six party talks."
|Abe downplayed the significance of |
the North Korean missiles [AP]
The US also played down the missile reports in relation to the six-way talks.
Christopher Hill, the US assistant secretary of state, said: "I do believe the DPRK [North Korea] continues to signal to us privately and publicly, and most recently last night, that as soon as the banking matter is resolved, they will move quickly to implement their part of the deal."
Last month, North Korea displayed a newly developed ballistic missile capable of reaching the US territory of Guam during a massive military parade.
The parade in Pyongyang featured three new models, including the medium-range missile that can travel 2,500-4,000km, South Korea's Chosun Ilbo newspaper reported.
In October North Korea conducted its first-ever test of a nuclear weapon.
However, intelligence experts in the region and in the US say North Korea is still some way off developing a nuclear warhead capable of being placed on a missile.
Increased naval defences
Also on Friday, South Korea bolstered its naval defences, launching its first destroyer that has been equipped with high-tech Aegis radar technology.
The 7,600-tonne class KDX-III destroyer is armed with an Aegis combat system, enabling the warship to detect and trace about 1,000 targets and then attack 20 of them at the same time, the navy said in a statement.
"We cannot preserve peace unless we have the ability to do so," said Roh Moo-hyun, the South Korean president, at the launching ceremony in the Korean city of Ulsan.
"We should ensure that we are able to defend ourselves not only in naval capabilities, but in all other areas of combat."
Seoul plans to launch two more Aegis-equipped destroyers by 2013.