South Korea and the US kicked off their annual joint military drill exercise aimed at deterring threats from North Korea, South Korea's Air Force said.

The drills are a part of the annual Ulchi Freedom Shield exercises that is set to continue until August 29.

They "reflect realistic threats across all domains," including cyber attacks, GPS jamming and the North's missiles, Seoul's Joint Chiefs of Staff said.

The exercises will boost the allies' "capability and posture to deter and defend against weapons of mass destruction," it added.

The exercise will see more than 200 South Korean and US fighter jets fly around the clock for five days this week.

The US stations 28,500 troops in the South for combined defense against nuclear-armed North Korea. 

What do we know about the drills?

About 19,000 South Korean troops will be joining the drills on land, sea and air, in addition to the cyber and space domains, according to the South Korean Defense Ministry. Officials have not disclosed details about the US involvement in the drills.

In Seoul, the city administration will hold simultaneous drills to prepare for North Korean drones and trash balloons. 

North Korea routinely denounces the annual Ulchi Freedom Shield drills for stoking tensions on the Korean Peninsula, calling them rehearsals for a nuclear war.

mfi/rm (AFP, Reuters)