Rwanda’s intelligence chief, Karenzi Karake, has been arrested in London.
Gen Karake, 54, wanted in Spain for war crimes, was arrested at Heathrow Airport on Saturday.
He was remanded in custody pending a court hearing on Thursday.
He is accused of ordering massacres while head of military intelligence in the wake of the 1994 Rwanda genocide.
According to BBC, Karenzi was arrested by Metropolitan police officers under the European Arrest Warrant.
But the Rwandan government is said to be puzzled by the timing of Gen Karake’s arrest, as he had travelled to the UK several times since the indictment was issued.
Gen Karake is also accused of ordering the killing of three Spanish nationals working for Medicos del Mundo.
In 2008, a Spanish judge indicted him for alleged war crimes along with 39 other current or former high-ranking Rwandan military officials.
Louise Mushikiwabo, Rwanda’s foreign minister called the arrest an outrage.
Williams Nkurunziza, Rwanda’s High Commissioner to the UK, called the arrest an insult.
“Any suggestion that any of our 40 leaders are guilty of crimes against humanity is an insult to our collective conscience,” Nkurunziza told BBC.
The British High Commission in Rwanda said the arrest was a legal obligation UK owes to Spain.
“We co-operate closely on a growing range of regional and international issues,” the commission said in a statement.
“Her Majesty’s government greatly values the close relationship with Rwanda and is committed to that relationship for the long term.”
Andrew Mitchell, former secretary of state for international development, thinks the arrest was a wrong move being used for “political reasons and not judicial ones”.
Gen Karake is director general of Rwanda’s National Intelligence and Security Services and a member of Rwandan Patriotic Front (RPF).
Nicknamed KK, the Rwandan government hail him as one of the people who stopped the genocide.
He went on to be deputy commander of the country’s first UN peacekeeping mission in Darfur before returning to his role as spy chief.
During the genocide an estimated 800,000 people were killed between April and June 1994 by ethnic Hutu extremists.