Three men were being held in custody Sunday on suspicion of conspiracy to murder the British soldier hacked to death in a London street in an Islamist attack.
Two men aged 28 an 24 were arrested at a home in southeast London on Saturday, with police firing a Taser electric stun gun on the older suspect, and on a 21-year-old man they arrested in a street around a mile (1.5 kilometres) from the murder scene.
Britain is dealing with the aftermath of a grisly murder which was the first fatal Islamist terror attack in the kingdom since the 2005 London bombings.
Prime Minister David Cameron is launching a new task force to tackle extremism and radicalisation, his Downing Street office said.
Meanwhile an inter-faith group reported a large spike in anti-Muslim incidents.
Drummer Lee Rigby, 25, who survived a tour of duty in Afghanistan, was butchered in broad daylight Wednesday outside the Royal Artillery Barracks in Woolwich, southeast London.
Michael Adebolajo, 28, and 22-year-old Michael Adebowale remain in a stable condition after being shot by police at the scene of the killing.
They have both been arrested on suspicion of murder and are under armed guard in separate hospitals.
The three men arrested Saturday on suspicion of conspiracy to murder were all held by detectives from the Counter Terrorism Command supported by specialist firearms officers.
Officers were also searching four residential addresses in southeast London.
Cameron's new counter-terror task force will include key cabinet ministers and bring in police and security chiefs when needed.
It will focus on radical preachers who target potential recruits in jails, schools, colleges and mosques. It was also to monitor trends in radicalisation and tackle "poisonous narratives".
Downing Street said the group would seek practical measures rather than getting bogged down in theoretical debates about Britishness and cultural values.
Writing in The Sunday Telegraph newspaper, Communities Secretary Eric Pickles urged politicians, judges and the public sector to take a robust line against extremists.
Meanwhile Britain's intelligence agencies were facing scrutiny following claims that the MI5 domestic security service had tried to recruit one of the two murder suspects.
Both men were known to the intelligence services and Adebolajo had links to the banned radical Al-Muhajiroun movement, but ministers and security experts have warned of the difficulty in keeping track of everybody with extreme views.
Both were brought up by Nigerian Christians and converted to Islam in their teens, and recently were seen handing out extremist literature in the streets -- to the concern of their families.
Newsapapers carried pictures of Adebolajo in court in the Kenyan city of Mombasa in November 2010.
The Mail on Sunday claimed he had been detained with others on suspicion of planning to fight for a terror group. The men were thought to have been heading to Somalia to join the Al-Qaeda-linked Shebab insurgents.
Adebolajo was deported to Britain without being charged, it said.
Adebolajo's friend Abu Nusaybah -- real name Ibrahim Hassan -- has told BBC television that MI5 visited Adebolajo after he returned from Kenya and tried to recruit him.
He also told The Mail on Sunday that MI5 wanted Adebolajo to spy on a group of Muslims with links to Al-Qaeda in the Arabian Peninsula.
"They wanted information about them," he said.
"They offered him money and they gave him a special mobile phone to use when calling them. They even took him in for interviews, just to intimidate him to work for them. But he refused."
On Friday, Hassan posted on Twitter that MI5 had tried to recruit Adebolajo. Within hours he gave the interview at the BBC, where he was arrested on suspicion of the "commission, preparation or instigation of acts of terrorism".
Faith Matters, a state-funded organisation which works to reduce extremism, said it has recorded a huge increase in anti-Muslim incidents reported to its helpline since the attack.
"It's a hugely worrying development," director Fiyaz Mughal told AFP, saying the organisation had been informed of 162 incidents in the past 48 hours, compared to a daily average of four to six.
They were mainly verbal attacks on women wearing the Islamic headscarf in the street, he said, but there were also online attacks and some violence.
A number of people have been charged over malicious comments made on social networking sites.
Meanwhile in Paris, a uniformed French soldier on anti-terror duties was stabbed in the neck Saturday in an attack that President Francois Hollande said could not "at this stage" be linked to the London murder.