SEOUL, May 27 (Xinhua) -- The Democratic People's Republic of Korea (DPRK) seems to have restarted its nuclear reprocessing facility at Yongbyon, South Korea's Yonhap News Agency said Wednesday, citing its source.

    "The Yongbyon nuclear facility was spotted to have opened several times the plutonium fuel rods in mid-April, in addition to smoke rising from the steam facility later in the month," the source was quoted as saying by Yonhap.

    As Reprocessing spent fuel rods is a key process to producing weapons-grade plutonium, Pyongyang is believed to possess enough plutonium to make as many as half a dozen nuclear weapons, according to Yonhap.

    As vehicles apparently conveying chemicals were also eyed near the Yongbyon facility, the DPRK seems to have followed pre-devised processes, one of which is the recent nuclear test, Yonhap said.

    "As a result, it is the belief of our intelligence office that it is highly likely the North restarted its nuclear facility," the source was quoted as saying.

    The DPRK has been going through a disablement process in the Yongbyon facility as it signed an aid-for-denuclearization deal in2007.

    Pyongyang said in April that it would restart the nuclear facility in protest of a U.N. Security Council statement that condemned its long-range rocket launch earlier that month.