South Korea's top security officials stressed the United States has no hostile intent toward North Korea, the presidential office Cheong Wa Dae said Wednesday, as Seoul steps up diplomacy to resume dialogue with Pyongyang.

The officials discussed efforts to reengage with the North during a standing committee session of the National Security Council led by National Security Office Director Suh Hoon, amid worrisome signs of the reclusive regime restarting a plutonium-producing nuclear reactor.

The participants agreed on the need to continue consultation with Washington over the allies' joint package of policy measures to resume nuclear diplomacy with Pyongyang, according to Cheong Wa Dae.

The participants also agreed to strengthen communication with other relevant countries for an early resumption of dialogue with the North.

Seoul has been revving up diplomacy to move forward its stalled agenda for lasting peace on the Korean Peninsula, as the International Atomic Energy Agency has said the North appears to have reactivated a key nuclear reactor at its mainstay Yongbyon complex.

Seoul and Washington have been discussing humanitarian assistance and other measures to encourage Pyongyang's return to dialogue, while the US special representative for the North, Sung Kim, reiterated Washington has no hostile intent to Pyongyang.

Nuclear talks between Washington and Pyongyang have remained stalled since the Hanoi summit between then US President Donald Trump and North Korean leader Kim Jong-un ended without a deal. (Yonhap)