In a brief despatch, which made no mention of the pontiff's five-day visit to the South, the North's official KCNA news agency said leader Kim Jong-Un had personally supervised the testing of a high-precision tactical missile.
The test was timed to mark the 69th anniversary today of the Korean peninsula's liberation from Japanese rule in 1945, it added.
The North fired three short-range missiles just minutes before the pope's plane touched down in Seoul yesterday morning at the start of the first papal visit to Asia for 15 years.
The KCNA despatch did not specify the time or date of the test supervised by Kim, but South Korean defence ministry officials said no other rockets had been detected, indicating that it referred to yesterday's launches.
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Speaking in Seoul later yesterday, Pope Francis said that peace could only be brought to the divided Korean peninsula through dialogue, not "displays of force".
According to KCNA, the testing was of an "ultra-precision high-performance tactical rocket" developed under Kim Jong-Un's guidance.
Pyongyang had trumpeted the test of a missile with a similar description in June, calling it a "cutting-edge" weapon that marked a breakthrough in national defence capability.
The United States denounced yesterday's launches and said it was studying whether they violated UN Security Council resolutions.
"We continue to call on North Korea to refrain from undertaking such provocative actions," State Department spokeswoman Marie Harf told reporters in Washington.
Harf also voiced concern that North Korea did not give notice to alert passing ships and aircraft.
North Korea has carried out an extended series of missile tests into the East Sea in recent months, despite UN resolutions barring it from any launches using ballistic missile technology.