A man was arrested today by counter-terrorism officers in connection with the death of Drummer Lee Rigby, Scotland Yard said.
Armed officers were involved in the arrest of the man, 22, on suspicion of conspiracy to murder, in St Paul's Road in Highbury Grove, north London, the Metropolitan Police said.
He is the fifth man to be arrested on suspicion of conspiracy to murder Drummer Rigby, 25, in Woolwich, south east London, last Wednesday.
A Metropolitan Police spokesman said: "At 2.35pm today a 22-year-old man was arrested by officers from the MPS Counter-Terrorism Command investigating the murder of Lee Rigby.
"The man was arrested on suspicion of conspiracy to murder by detectives supported by specialist firearms officers.
"He has been taken to a south-London police station where he remains in custody.
"He was arrested in St Paul's Road, in Highbury Grove, north London."
The latest arrest came hours after members of the serviceman's family visited the scene of his murder.
His widow Rebecca, mother Lyn, 46, and stepfather Ian, 54, laid flowers at the Woolwich Barracks where the soldier with the Royal Regiment of Fusiliers was based, and where hundreds of floral tributes have already been left by wellwishers.
Their visit came as Home Secretary Theresa May warned today there are potentially thousands of people at risk of being radicalised in the UK, as she indicated plans for a fresh crackdown on extremist groups.
Nine people have now been arrested in connection with Drummer Rigby's death.
Michael Adebolajo, 28, and Michael Oluwatobi Adebowale, 22, who are being held on suspicion of murder, remain in hospital.
Three men aged 28, 24 and 21 remain in police custody after being arrested yesterday on suspicion of conspiracy to commit murder.
A 29-year-old man arrested on suspicion of conspiracy to murder has been released on bail, police said last night.
Two women aged 29 and 31 who were held on Thursday on suspicion of conspiracy to commit murder have been released without charge.
A Foreign Office spokeswoman confirmed that a British national was arrested in Kenya in 2010. "FCO provided consular assistance as normal for British nationals," she said.