(VOVworld) – On Tuesday, the United States urged North Korea to refrain from "irresponsible provocation" after it confirmed the restarting of a nuclear reactor seen as its main source of weapons-grade plutonium.

US urges North Korea to avoid 'provocations' over nuclear program (Photo: AFP)

White House spokesman Josh Earnest said: "North Korea should refrain from irresponsible provocation that serves only to aggravate regional tensions." On the same day, spokesperson for the US Department of State John Kirby also asked Pyongyang to refrain from provocative acts.

Earlier, the North’s official KCNA news agency reported that the country’s atomic energy scientists had been "steadily improving" both the quality and quantity of the North's nuclear deterrent. It says all facilities at the Yongbyon nuclear complex -- including the five-megawatt reactor -- had "started normal operations".