Russia on Tuesday expressed its concern over the Republic of Korea's pursuit of longer-range missiles under a revised pact with the United States, warning that the move may lead to new arms race on the Korean Peninsula.

"We have invariably reaffirmed our negative attitude to the leadership of the Republic of Korea (ROK) over these intentions, which are potential sources of further exacerbation of military- political situation on the Korean Peninsula and a new round of arms race," Russian Foreign Ministry spokesman Alexander Lukashevich commented on the ministry website.

Russia called upon all interested parties to avoid new actions to further aggravate the situation and urged them to exert restraint in a responsible way, Lukashevich said.

He also stressed that the only effective way to defuse tensions on the Korean Peninsula was to give up using military methods and resume the six-party talks.

"We assume that the relaxation of tensions in Northeast Asia is a shared task of all the states in the region," the spokesman added.

The Democratic People's Republic of Korea (DPRK) said Tuesday that the U.S. mainland is within the target range of its strategic rocket forces.

The announcement came after the ROK presidential office said Sunday that under the revised pact with the United States, Seoul planned to develop ballistic missiles with a tripled range of 800 kilometers, which could cover the entire peninsula, as part of its efforts to better respond to perceived missile threats from the DPRK.