LONDON (TheBlaze/AP) — Police on Monday arrested a 10th suspect in connection with the vicious killing of an off-duty British soldier on a London street in an apparent terrorist attack by Islamic extremists.

The 50-year-old man was detained in Welling, east of London, on suspicion of conspiring to murder 25-year-old soldier Lee Rigby, Scotland Yard said. Police didn’t provide further details about the suspect’s identity.

The latest arrest came as around 1,000 supporters of a far-right group marched through central London protesting the killing, clashing with a smaller group of anti-fascist demonstrators.

Police have already taken nine other suspects into custody, including the two main ones who were shot and wounded by officers at the scene of Wednesday’s killing. Michael Adebolajo, 28, and Michael Adebowale, 22, remain under armed guard in separate London hospitals. Four other men remain in custody at a London police station.

British Police Arrest 10th Suspect in Horrific Woolwich Terror Attack

This undated image released Thursday May 23, 2013, by the British Ministry of Defence, shows Lee Rigby, known as Riggers to his friends, who is identified by the MOD as the serving member of the armed forces who was attacked and killed by two men in the Woolwich area of London on Wednesday. Credit: AP

Witnesses say Rigby, who had served in Afghanistan, was walking near his barracks in southeast London’s Woolwich area when he was run over by a vehicle and repeatedly stabbed with knives and meat cleavers.

The gruesome scene was recorded on witnesses’ cellphones, and a video picked up by British media showed one of the two main suspects, holding a bloody knife and cleaver, making political statements and warning of more violence. Hard-line Muslim leaders have identified the man in the video as Adebolajo.

Kenyan officials have confirmed that Adebolajo was arrested in Kenya in 2010 with five others near the country’s border with Somalia. Police believed Adebolajo was going to work with Somali militant group al-Shabab.

British Police Arrest 10th Suspect in Horrific Woolwich Terror Attack

Protesters display a flag of St. George as they join an English Defence League march down Whitehall towards Downing Street on May 27, 2013 in London, England. The EDL are protesting what they see as a lack of support and protection given to British troops following the terror attack last week, in which soldier Drummer Lee Rigby was murdered in a knife and machete attack by two Muslim men outside Woolwich Barracks. (Photo: Getty Images)

The killing in London has fed a spike in anti-Muslim sentiment in Britain, with police and activists reporting a surge in hate crimes, including violence and vandalism.

A mosque in the northern England town of Grimsby was firebombed Sunday night, according to the mosque’s chairman, Diler Gharib, who told a local newspaper he was discussing how to thank his neighbors for the support they had shown his community in the past days when the building was hit with gasoline bombs.

Police said they arrested two people in connection with the incident. The fire was extinguished, and no one was injured, they said.

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