Rwanda's foreign minister has said that the arrest of the country's intelligence chief in London is "lunacy".

British police arrested the director-general of Rwanda's National Intelligence and Security Services, Karenzi Karake, on Saturday at the request of Spain, where he is wanted in connection with war crimes.

Karake was arrested at London's Heathrow Airport, British police said in a statement on Monday.

"Karenzi Karake, 54, a Rwandan national appeared before Westminster Magistrates' Court ... after being arrested on a European Arrest Warrant on behalf of the authorities in Spain, where he is wanted in connection with war crimes against civilians," police said.

Karake was remanded in custody to reappear at the court on Thursday.

Rwanda's foreign minister, Louise Mushikiwabo, was critical of the arrest , calling it "unacceptable" in a tweet.

"Western solidarity in demeaning Africans is unacceptable!! It is an outrage to arrest #Rwanda-n official based on pro-genocidaires lunacy!" Mushikiwabo said.

It was not immediately possible to contact Karake's family or his lawyers and there was no response from the Rwandan embassy in London.

Rwanda's Justice Seekers

In 2008, a Spanish High Court judge, Fernando Andreu, accused 40 Rwandan military and political leaders, including Karake, of engaging in reprisal killings after the country's 1994 genocide.

The judge indicted the officials for genocide, crimes against humanity and terrorism, which resulted in the deaths of hundreds of thousands of civilians, including Spaniards.

Speaking to the New Times newspaper, Rwandan justice minister Johnston Busingye said Kigali was discussing the matter with the UK government. 

 "I would be surprised if [the Spanish warrant] is one the UK is acting on. We will contest in the courts. We have sought explanation from the UK on this matter as well," Busingye told the newspaper.

Source: Al Jazeera and agencies