SEOUL, Jan. 6 (UPI) -- A South Korean Defense Ministry study indicates North Korea has made progress toward building nuclear warheads capable of delivery by missile. "North Korea's capabilities of miniaturizing nuclear weapons appear to have reached a significant level," it said, although a ministry official acknowledged there is no intelligence information to support that conclusion, the South Korean Yonhap News Service reported Tuesday.
The official said it has been eight years since North Korea conducted its first nuclear test, enough time to develop appropriate technology for a missile-launched warhead. Pyongyang has conducted three nuclear tests, most recently in 2013.
Shrinking a warhead to fit atop a missile implies it could be fired at another country.
The report says North Korea is believed to have 88 pounds of weapons-grade plutonium, and is working to produce highly enriched uranium.
The release of the report comes as South Korea and China reinforced their agreement on a zero-tolerance policy on North Korean nuclear weapons with talks Monday between defense and foreign ministry representatives of Seoul and Beijing.
"The two sides agreed to further strengthen bilateral and multilateral cooperation for peace and security on the Korean Peninsula," an unidentified South Korean official said.
Although North Korea has said it seeks a resumption of talks over its weapons program, stalled since 2008, both Washington and Seoul have insisted Pyongyang must first demonstrate its interest in de-emphasizing nuclear weapons.