ABU DHABI, 24th February 2016 (WAM) — The top U.S. military commander in South Korea said Tuesday that North Korean leader Kim Jong Un would use a weapon of mass destruction if he thought the fate of his rule was at stake.

If he “thought his regime were challenged he states that he would use WMD,” Gen. Curtis Scaparrotti, commander of U.S. Forces Korea, told the Senate Armed Services Committee Tuesday, the American Cable News Network (CNN) reported.

Scaparrotti said that tensions on the Korean Peninsula were at their highest level in more than 20 years.

Adm. Harry Harris, commander of U.S. Pacific Command, said at the same hearing that if North Korea continues to develop ballistic missiles, a U.S. military option is possible.

The North Korean military warned the U.S. and South Korea Tuesday to expect retaliations for their annual joint military drill in March. The warning came in a statement released Tuesday via state media agency KCNA.

The U.S. maintains nearly 30,000 troops in South Korea.

North Korea’s recent nuclear and long-range missile tests have prompted formal discussions on the deployment of the THAAD missile defense system, which can target short, medium and intermediate ballistic missiles in flight.