TOKYO- Japan's top government spokesman has called a North Korean threat to sink Japan with a nuclear bomb extremely provocative and outrageous.

Chief Cabinet Secretary Yoshihide Suga said Thursday that the statement distributed by North Korea's state news service "significantly escalates tensions in the region."

The statement from a group called the Korea Asia-Pacific Peace Committee attacked the United States for leading a push for stronger U.N. sanctions against North Korea, as well as Japan for joining the U.S. campaign.

The U.N. Security Council unanimously approved new sanctions Monday following North Korea's sixth and strongest nuclear test on Sept. 3. Although not as tough as what the U.S. had sought, the sanctions are expected to have a significant impact.