Citing an anonymous military official in Seoul, South Korea's Yonhap news agency said the short-range missile launch came a day after Pyongyang fired three short-range guided missiles into the same body of water.
"Following yesterday (Saturday), North Korea launched one short-range missile into the East sea this afternoon (Sunday)," Xinhua quoted the official as saying.
Seoul's unification ministry in charge of inter-Korea affairs condemned Saturday's launch by North Korea as "provocative".
On a visit to Moscow, the UN secretary general Sunday said he was concerned over North Korea's latest short-range missile launches and called on Pyongyang to return to the six-party talks on its controversial nuclear programme.
The communist regime broke off talks with South Korea, China, the US, Japan and Russia on its nuclear programme in 2009, after the UN Security Council passed a resolution condemning its missile tests.
"I hope North Korea will refrain from further such acts," Russia's RIA Novosti news agency quoted Ban as saying.
He added that it was time for Pyongyang to return to dialogue and ease tensions on the Korean peninsula and that the UN was ready to help.
Tensions rose on the Korean Peninsula in December after North Korea tested a Taepodong 2 missile and again in February when it carried out its third nuclear test.
The UN hit back with sanctions, and the start of joint military drills between South Korea and the US in March further irritated the North, which threatened to carry out a nuclear attack on the US mainland, as well as on US forces in the region.
North Korea has been subjected to several rounds of UN Security Council sanctions since it declared itself a nuclear power in 2005.
--IANS (Posted on 19-05-2013)