North Korea has declared that the raid on its embassy in Madrid in February was “a grave terrorist attack” and demanded that Spanish authorities “bring the terrorists and their wire-pullers to justice”.

In a comment on Sunday to state-run media in Pyongyang, a spokesman for the North Korean foreign ministry said “armed robbers” had stabbed, beaten, tortured and humiliated staff at its embassy in Madrid. “Illegal invasion, occupation and robbery of diplomatic missions are a severe violation of national sovereignty and a violent violation of international law, which should never be permitted," it added.

Spanish authorities announced on Tuesday that they are seeking 10 men who allegedly entered the embassy on Feb. 22, armed with knives, metal bars and dummy guns, before tying staff up and trying to convince the economics officer to defect. The group, which included Adrian Hong Chang, a Mexican citizen, as well as a US national and five South Koreans, reportedly took a number of computers, data discs and mobile phones before making their escape.

It was not until March 26 that Free Jeoson - which was previously known as the Cheollima Civil Defence group and was reportedly founded by Mr Hong - broke its silence to take the credit for the raid. Mr Hong is understood to have immediately flown to the United States to hand over the information gathered in the incident to the FBI.