MADRID - An organisation committed to overthrowing North Korea's leader Kim Jong-un has claimed it was behind a raid at Pyongyang's embassy in Spain.

Cheollima Civil Defense, a self-styled human rights group, reportedly fled with computers, a phone and hard disks.

The group denied using force in the 22 February incident, saying it was "not an attack".

However, a Spanish high court judge said the 10 assailants shackled, beat and interrogated embassy staff.

It remains unclear why the raid took place. Cheollima wrote online that it had "responded to an urgent situation in the Madrid embassy".

The group added: "It is to protect those who seek our help, and those who take great risk to protect others, that we cannot share more about the event at this time."

It said it had "shared information of enormous potential value" with the FBI, the US intelligence agency, "under mutually agreed terms of confidentiality".

The break-in occurred just days before a key summit between US President Donald Trump and North Korean leader Kim Jong-un in Hanoi, Vietnam.(FA)