Rodong Sinmun, North Korea's official newspaper, said the volunteers had offered to join or rejoin the People's Army after the Korea Central News Agency (KCNA) issued a statement on Monday condemning new sanctions imposed by the United Nations in retaliation for North Korean missile tests.
Earlier this week, nuclear-armed North Korea threatened to strike the United States and its Pacific territory of Guam.
KCNA said on Wednesday a mass rally was held in Pyongyang to support the government. North Korea has previously mobilized large crowds to show its resolve when tensions escalate.
In August 2015, 1 million North Koreans offered to enlist or re-enlist in the army when a mine exploded in the demilitarized zone between the two Koreas, raising additional tensions.
North Korea warned foreign diplomats to leave Pyongyang in 2013 when it suspended work at a joint inter-Korean industrial park and threatened missile strikes on U.S. Pacific bases, notably in Guam and Hawaii.