A 50-year-old man was arrested today in connection with the murder of soldier Lee Rigby in Woolwich, Scotland Yard said.
The suspect was arrested in Upper Wickham Lane, Welling, south east London, Scotland Yard said. An address is also being searched in south east London.
The arrest is the tenth officers have made over the murder of Drummer Lee Rigby, 25, who was hacked to death in the street by Islamic extremists last week.
Earlier, three men arrested on Saturday over Drummer Rigby's killing were released on bail.
The developments came after the Home Secretary Theresa May strongly indicated she would seek to revive legislation giving security agencies access to public communications data.
She told the BBC's Andrew Marr show: "We are now working through across the government what action we can take but I'm clear, the law enforcement agencies, the intelligence agencies need access to communications data and that is essential to them doing their job.''
Her revelation came after Downing Street confirmed the launch of a new terror taskforce to crack down on extremism.
The group, comprising Cabinet ministers and top police and security service officials, will focus on radical preachers who seek out potential recruits in prisons, schools, colleges and mosques.