A South Korean court has sentenced former President Yoon Suk Yeol to 30 years in jail for sending drones into North Korea.

Prosecutors argued that Yoon ordered the operation in October 2024 to provoke Pyongyang and create a pretext for his failed martial law bid later that year.

When Yoon declared martial law on 3 December, he had claimed he was protecting the country from "anti-state" forces that sympathised with North Korea. But it soon became clear he was driven by domestic troubles, and he rolled back the order in the face of mass protests.

Yoon was impeached and is now serving time in prison after he was sentenced to life for insurrection over his botched martial law attempt.

On Friday, the Seoul District Court found Yoon, as well as his former defence minister Kim Yong-hyun, the former head of the Defence Counterintelligence Command Yeo In-hyung, and the former head of the Drone Operations Command Kim Yong-dae, guilty of treason and abuse of power.

Kim was sentenced to 30 years in prison, while Yeo received 15 years, and Kim Yong-dae received 3 years in prison with a 5-year suspended sentence.

"The defendants used the guise of a military operation to induce provocations from North Korea with the aim of creating a state of emergency," the court said.

It added that all three officials had "provoked North Korea", thus "increasing the risk of a military conflict", but concluded that Yoon bore the "greatest responsibility" in this event.

Yoon's lawyers had argued that his actions were a "legitimate" response to North Korea's "provocations with rubbish balloons".

This was a reference to North Korea dropping hundreds of balloons in 2024, which were later found to contain "filthy waste and trash", across the border in the South.

The two countries have used such "propaganda balloons" in their campaigns since the Korean War, with messages placed inside them.

But tensions shot up in 2024 when North Korea accused the South of flying drones into its capital. These drones allegedly scattered propaganda leaflets all over Pyongyang, in what the North described as a provocation that could lead to war.

It was Yoon who sent these drones into the North, expecting it to strike back, said a judge in Friday's ruling.

Apart from insurrection, Yoon was also sentenced to five years in jail for abuse of power and obstructing his own arrest.

Yoon's attempt at martial law and the protests that followed created months of chaos in the country, culminating in an election in which the opposition Democratic Party's Lee Jae-myung won a decisive mandate.