LOS ANGELES (Reuters) - U.S. authorities are focused on Southern California in their manhunt for a one-time human rights activist accused of leading a violent takeover of North Korea’s embassy in Spain, according to a federal arrest warrant unsealed on Friday.

FILE PHOTO: A Spanish National Police car is seen outside the North Korea's embassy in Madrid, Spain February 28, 2019. REUTERS/Sergio Perez/File Photo

Adrian Hong Chang is wanted by Spain in connection with the alleged embassy raid in February, but his lawyer denounced the U.S. Justice Department for seeking his arrest and extradition based on “the highly unreliable accounts of North Korean government witnesses.”

The warrant, citing information from Spanish authorities, describes Hong Chang as the mastermind of a raid by seven individuals on the North Korean Embassy in Madrid on Feb. 22 that began with Hong Chang posing as a visiting businessman.

He and six fellow intruders, armed with knives, iron bars, machetes and imitation pistols, then stormed the embassy, restrained and physically beat the charge d’affaires and several other employees and held them captive for several hours before fleeing the compound, according to the warrant.

They got away with computer equipment and a mobile phone stolen from the embassy, which Hong Chang, also known as Adrian Hong, presented days later to the FBI in New York after fleeing back to the United States, the warrant says.

A Spanish judicial court said earlier this week that the FBI later handed the material over to Spanish authorities who have since returned it to Pyongyang’s mission in Madrid.

The incident at the embassy came at a sensitive time, just days ahead of a second summit between U.S. President Donald Trump and North Korean leader Kim Jong Un that abruptly collapsed without the two men reaching a deal on Pyongyang’s nuclear weapons program.

North Korea’s foreign ministry denounced the incident as a “grave terrorist attack” and cited rumors that the FBI was partially behind the raid. The U.S. State Department has said Washington had nothing to do with it.

Spain is seeking Hong Chang’s extradition to face charges of breaking and entering, illegal restraint, robbery, causing injuries and being a member of a criminal organization.

Similar charges are pending against an accused accomplice, Christopher Philip Ahn, 38, a former U.S. Marine who was arrested April 18 in Los Angeles on a separate warrant stemming from the same incident. He remains in U.S. custody.

Spanish authorities have described Ahn as belonging to a group that calls itself Cheollima Civil Defense and seeks the overthrow of the Kim government. The anti-Kim group, which also calls itself Free Joseon, has denied attacking the embassy in Madrid and insisted its members were invited inside.

Hong Chang, a Mexican citizen who holds permanent U.S. residency, was an activist who co-founded the non-profit human rights group Liberty in North Korea but later left that organization.

His lawyer, Lee Wolosky, who also represents Free Joseon, accused U.S. authorities of accepting at face value a false North Korean account of events.

“In due time, we expect to be able to present additional evidence that contradicts the story made up by the North Korean government,” Wolosky said.

The warrant for Hong Chang’s arrest said U.S. authorities had traced his home to a Los Angeles address and believed he remains at large somewhere within the U.S. Central District of California, an area comprising Los Angeles and adjacent counties.