South Korea fires warning shots as North Korean drones enter airspace for the first time in 5 years, South Korea says

• North Korean drones entered South Korean airspace on Monday for the first time since 2017.
• South Korea responded by firing warning shots and scrambling fighter jets.
• North Korea has significantly ramped up its missile testing this year. 

Five North Korean drones crossed the border into South Korea on Monday for the first time in five years, heightening tension between the two neighbors. 

One drone traveled as far as the northern part of Seoul, South Korea's capital, about an hour's drive from the border, a South Korean defense official said in a briefing. The other four flew around Ganghwa Island, a CNN report said. 

The South Korean military responded by firing shots at the drones, though the country's defense ministry could not confirm if any drones were shot down.

"This is a clear provocation, and an invasion of our airspace by North Korea," South Korean defense official Lee Seung-oh said during a briefing.

Lee said the South Korean military conducted a reconnaissance mission after the drones entered its airspace, with some assets crossing into North Korean territory and filming its military installations. 

The last time a North Korean drone entered South Korean airspace was five years ago, according to the South Korean military. 

In 2017, South Korea said it had recovered a crashed North Korean drone that was spying on a U.S.-built missile system being deployed in the country, according to a CNN report from that time. 

North Korea has aggressively ramped up its missile tests this year, firing missiles on 36 separate days, the highest annual tally since Kim Jong Un took power in 2012, according to CNN. 

On Friday, South Korea said North Korea launched two short-range ballistic missiles, according to CNN.