South Korea warned Japan on Thursday against undermining efforts to force North Korea to abandon its nuclear weapons, after Tokyo announced the lifting of selected sanctions on Pyongyang.

Japanese Prime Minister Shinzo Abe said a number of unilateral sanctions would be revoked after progress in talks with the North over its Cold War kidnapping of Japanese nationals.

In a statement, the South Korean foreign ministry said it recognised the "humanitarian" nature of Japan's concern over the kidnapping issue.

But it also stressed that any discussions between Japan and North Korea on pending issues, including the lifting of sanctions, had to be done in a "transparent" fashion.

"And any measures taken by the Japanese government should not hurt international coordination among South Korea, the United States and Japan over North Korea's nuclear and missile programmes," it added.

The United States and its two main military allies in Asia have generally kept up a united front on the North Korean nuclear issue.

But a deepening rift between Seoul and Tokyo -- related to disputes dating back to World War II and Japan's colonial rule over the Korean peninsula -- has made the alliance look increasingly fragile.

South Korean officials say Pyongyang is using the kidnapping issue to exploit that fragility and push Tokyo towards a more independent North Korea strategy.

N. Korea vows further tactical guided-missile tests
Seoul (AFP) July 03, 2014 - North Korea vowed Thursday to push ahead with further strategic guided-missile tests, defying international calls to curb its weapons programme as the Chinese president arrived in Seoul for a visit seen as a snub to Pyongyang.

"(North Korea) will continue to hold drills of launching high-precision tactical guided missiles," said a spokesman for the Korean People's Army (KPA) Strategic Force, calling the tests a "legitimate exercise" of sovereignty.

North Korea has conducted a series of missile tests in the past week -- seen by some a display of pique with Chinese President Xi Jinping's two-day state visit to Seoul.

China is North Korea's sole major ally, but while Xi has met four times with South Korean President Park Geun-Hye -- including two summits -- he has yet to sit down with North Korean leader Kim Jong-Un.

The United States criticised the recent missile launches as "problematic" and "destabilising", while Seoul and Tokyo also lodged protests.

The first in the series of tests last Thursday was hailed by the North's state media as that of a new "cutting-edge" guided missile which marked a "breakthrough" in the North's military capabilities.

The South said the second test on Sunday was of two short-range Scud missiles with a range of about 500 kilometres.

On Wednesday the North fired two rockets with a range of around 180 kilometres (110 miles).

The South said there were a number of possible motives for the multiple tests, ranging from a display for domestic consumption, to a show of strength for the international community or a warning to Seoul.