North Korea says more than 800,<> citizens have volunteered to join its military to fight "US imperialists," the North's official KCNA news agency reported, two days after Pyongyang tested an intercontinental ballistic missile.

The young volunteers are "determined to ruthlessly eliminate war geeks" so they joined the military "to defend the country," the agency said, adding that "more than 800,<> officials and students from all over the country volunteered to join the Korean People's Army."

Photos released by North Korean official Rodong Sinmun showed young North Koreans waiting in long lines to register their names.

Reply to Exercises

After a record year of weapons tests and growing nuclear threats from Pyongyang, Seoul and Washington have stepped up their security cooperation, and this week began their biggest joint military drills in five years.

North Korea views the drills as an attack and has repeatedly warned it will take "crushing" action in response.

North Korea's official news agency described the ongoing drills as a U.S. attempt to "provoke a nuclear war," noting that hundreds of thousands of people had been recruited in response.

North Korea said on Thursday it had tested an intercontinental ballistic missile called Hwasong-17, and North Korea's official news agency called the missile test "a stern warning to enemies who deliberately escalate tensions on the Korean Peninsula."

Last week, North Korean leader Kim Jong Un ordered his military to step up military exercises in preparation for a "real war."