British police have arrested three more persons in connection with the murder of a soldier who was beheaded on a busy London street this week by two suspected Islamist extremists.

Two men, aged 24 and 28, were detained at an address in southeast London on Saturday, while a 21-year-old man was arrested in the street in Charlton Lane, Greenwich, all of whom were held on suspicion of the conspiracy to commit the murder of soldier Lee Rigby in Woolwich on Wednesday.

Police from the Counter Terrorism Command supported by specialist firearms officers, used tasers to detain the 21-year-old and the 28-year-old. They did not need hospital treatment.

The suspects arrested were not named by the security agencies.

The arrests came as Downing Street confirmed the launch of a new terror task force to crack down on extremism.

The group, comprising of 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.

Prime Minister David Cameron has also announced that the parliamentary Intelligence and Security Committee (ISC) will carry out an investigation following the disclosure that the two men suspected of the murder, identified as Michael Adebolajo, 28, and Michael Oluwatobi Adebowale, 22, were known to MI5.

Police on Saturday night refused to comment on reports that Adebowale was arrested two months ago.

Authorities in France were also investigating whether the murder of Rigby was linked to an attack on a French soldier, who was stabbed in the neck in a busy shopping area near Paris on Saturday.

The latest arrests in London took place on Saturday evening, and the three men are being held at a south London police station, Scotland Yard said.

Officers were on Saturday night also searched four addresses in southeast London.

Searches have also taken place at three other addresses in south London, one in east London, one in north London and one in Saxilby, Lincolnshire, the former home of Adebolajo.

A 29-year-old man arrested earlier on suspicion of conspiracy to murder has now been released on bail, police said on Saturday night.

Two women aged 29 and 31 have also been released without charges after they were held on Thursday on suspicion of conspiracy to murder, and a number of other people not directly involved with the attack have been charged over malicious comments made on social networking sites.

Adebolajo and Adebowale remained in a stable condition in hospital after being shot by police.

Rigby was hit by a car and then attacked with weapons including a knife and a meat cleaver on May 22. The cause of his death has not yet been confirmed by a post-mortem examination.

The young father’s murder has provoked a backlash of anger across the country, with mosques being attacked, widespread racial abuse, comments on social media and a large increase in anti-Muslim incidents.

Up to 2,000 people took part in an English Defence League march in Newcastle on Saturday, which had been planned before Wednesday’s attack.

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