TOKYO (AP) — North Korea says it wants an investigation into an attack on its embassy in Spain last month, calling it a "grave terrorist attack" and an act of extortion that violates international law.

The incident occurred ahead of President Donald Trump's second summit with leader Kim Jong Un in Hanoi on Feb. 27-28. A mysterious group calling for the overthrow of the North Korean regime has claimed responsibility.

The North's official media quoted a Foreign Ministry spokesman as saying that an illegal intrusion into and occupation of a diplomatic mission and an act of extortion are a grave breach of the state sovereignty and a flagrant violation of international law, "and this kind of act should never be tolerated."

He claimed an armed group tortured the staff and stole communications gear.