MOSCOW, May 30 (Xinhua) -- Russian President Dmitry Medvedev and Japanese Prime Minister Taro Aso have concurred on the need for a strong response to the nuclear test conducted by the Democratic People's Republic of Korea (DPRK), the Kremlin press service said on Saturday.

    "The parties agreed that it is necessary to most seriously respond to these steps, which represent a challenge to the international security system," the press service said after phone talks between the two leaders.

    Russia and Japan also agreed to coordinate on responsive measures ahead of a new United Nations Security Council resolution concerning the nuclear test, the press service said.

Japanese Prime Minister Taro Aso (L) and Russian President Dmitry Medvedev (2nd L) tour a liquefied natural gas (LNG) tanker at the newly-opened LNG plant on Sakhalin Island outside Korsakov some 50 km (31 miles) from Yuzhno-Sakhalinsk February 18, 2009

    The DPRK earlier this week conducted an underground nuclear test and launched several short-range missiles in defiance of previous UN resolutions.

    The UN Security Council said it would seek a new resolution against the DPRK because of the testing.