North Korea’s 1.1 million strong Korean People’s Army, or KPA, is nearly double the size of the 640,000-person South Korean military and the 28,000 U.S. troops stationed in Korea.

Much of North Korea’s military is believed to be decrepit: It lacks fuel, fields outdated equipment, and some troops are undernourished, but it wields two niche threats: special forces and artillery.

In a report in March last year, the commander of U.S. and U.N. forces in South Korea, General James Thurman, warned that North Korea has continued to improve the capabilities of the world’s largest special operations force — highly trained specialists in unconventional, high-risk missions.

Pyongyang fields 60,000 special forces, according to Gen. Thurman — and more than 13,000 artillery pieces, most of it deeply dug in along the DMZ, and ranged on Seoul; the dense capital sprawls just 30 miles (48 kilometers) south of the border.