British police have arrested the head of Rwanda's intelligence service on a warrant from Spain where he is accused of involvement in war crimes linked to the genocide, prompting a furious reaction from Rwanda.
The police said 54-year-old Karenzi Karake was arrested at Heathrow airport on Saturday and was due to appear in court in London on Thursday.
Rwanda's foreign minister slammed the arrest, which is linked to Karake's alleged participation in revenge massacres following the 1994 genocide.
"Western solidarity in demeaning Africans is unacceptable!!" Foreign Minister Louise Mushikiwabo said on Twitter. "It is an outrage to arrest Rwandan official based on pro-genocidaires lunacy!"
Rwandan Minister for Justice Johnston Busingye said he had "sought explanation" from British authorities, according to Rwanda's New Times newspaper.
Karake had been "on official duty in London for one week", the report added.
A British police spokesman said Karake was "arrested on a European arrest warrant on behalf of the authorities in Spain, where he is wanted in connection with war crimes against civilians".
A Spanish court seven years ago listed Karake in a roll-call of 40 army officers it intended to prosecute for genocide and crimes against humanity in Rwanda during the 1990s.
The BBC reported that the Rwandan government was puzzled by the timing of the arrest as Karake had travelled to Britain several times since the indictment.
The court's decision followed an investigation into the murder of nine Spaniards in Rwanda between 1994 and 2000 who were working with refugees.
The 2008 charge sheet said that Karake was accused of ordering massacres in an area in which three Spanish citizens working for the charity Medicos del Mundo were also killed.
But Busingye was dismissive of the legal basis of the warrant.
"I would be surprised if it is one the UK is acting on. We will contest in the courts," the justice minister said.
- 'Painful and violent episodes' -
Karake is part of an exclusive circle of top military officers in the former Rwandan Patriotic Front (RPF) rebel movement which brought an end to the 1994 genocide.
The RPF ethnic Tutsi rebel force ended the genocide by Hutu extremists that left an estimated 800,000 mostly Tutsis dead.
Like others, Karake's fortunes have risen and fallen under President Paul Kagame's rule. In 2010 he was placed under house arrest for misconduct but was later released.
Karake, known as KK, is also a former deputy chief of the United Nations-African Union peacekeeping force in Sudan's war-torn Darfur region.
Human Rights Watch criticised his 2007 appointment, saying Karake was responsible for the killings of civilians in the town of Kisangani, Democratic Republic of Congo, in June 2000.
The indictments issued in February 2008 by Spanish judge Fernando Andreu have been controversial and criticised as politically-motivated.
A 2008 diplomatic cable sent from the US embassy in Kigali and released by WikiLeaks dismissed the Spanish indictments as "outrageous and inaccurate".
"The Spanish indictment of 40 Rwandan military officers offers an unrecognizable version of some of the most painful and violent episodes in Rwanda's history," said the cable, which described the allegations as "a bloated political tract, sloppily organized and endlessly repetitive".