The North Korean embassy break-in in Madrid was “a grave terrorist attack,” according to a spokesperson from the North Korean Foreign Ministry.

“An illegal intrusion into and occupation of diplomatic mission and act of extortion [sic] are a grave breach of the state sovereignty and a flagrant violation of international law, and this kind of act should never be tolerated,” said the spokesperson in remarks published on Sunday by the Korean Central News Agency (KCNA).

This is one of the most serious diplomatic incidents to take place on Spanish territory

This is the first reaction from Pyongyang to the incident that took place on February 22, when a group of 10 individuals broke into the diplomatic building, restraining and assaulting the eight people inside with the aim of finding and stealing “sensitive information on North Korea’s nuclear and weapons program,” according to Spanish police sources.

The Pyongyang spokesperson told the KCNA that they expect Spanish authorities to carry out an investigation “in order to bring the terrorists and their wire-pullers to justice in conformity with the relevant international law.”

The English version of the ministry statement, as published by the KCNA, also says verbatim that “we are following the rumors of all hues now in the air that FBI of the United States and the small fry of anti-DPRK ‘body’ [sic] were involved in the terror incident.”

The police investigation points at “a mercenary of North Korean origin” as the mastermind

The attack took place five days before a summit between North Korean leader Kim Jong-un and US President Donald Trump in Hanoi, Vietnam. The meeting ended abruptly without a deal.

This is one of the most serious diplomatic incidents to take place on Spanish territory, and both police and intelligence service (CNI) sources said that at least two of the intruders have ties to the CIA. Last week, Trump denied that these events have “anything do with the United States.” No member of the Spanish government has made any statements on the matter to date.

During the assault, embassy staff members were handcuffed, interrogated and beaten, according to José de la Mata, the investigating judge at Spain’s High Court, the Audiencia Nacional.

The police investigation points at “a mercenary of North Korean origin” as the mastermind behind the break-in. Adrian Hong Chang, 35, who is a US resident with Mexican citizenship, “is the owner of several dubious businesses and he is in contact with several intelligence services,” according to sources familiar with the matter. These same sources said that further investigations are underway to determine whether Hong Chang has been involved in other violent incidents against North Korean interests in other countries.

The judge’s report said that seven of the assailants have been identified, including Hong Chang and a US national named Sam Ryu. De la Mata has requested their extradition from the US, where they fled following the attack on the Madrid embassy. The other intruders are South Korean nationals with US residency.