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 Friday 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 on Thursday morning at the start of the first papal visit to Asia for 15 years.
Another two rockets were fired later in the day.
Speaking in Seoul later Thursday, 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.
North Korea is not known to have a tactical guided missile, but analysis of a recent propaganda film suggested it may have acquired a variant of a Russian cruise missile, the KH-35.
The United States denounced Thursday'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.
The North has defended the tests as a legitimate exercise in self-defence and a response to war manoeuvres involving the US and the South. (AFP)