British police have arrested a tenth suspect in connection with the street killing of a soldier in London, an attack that has heightened racial tensions in the country.
This developed as Britain's parliamentary intelligence committee said on Tuesday that it will carry out a report into whether UK intelligence services fell short before the killing of 25-year-old Lee Rigby.
Malcolm Rifkind, chair of Parliament's Intelligence and Security Committee, was quoted as saying that MI5 has pledged to cooperate as the committee tries to "get to the bottom: of the agency's work.
He said the committee will "go where the evidence takes us'' and judge if there was a problem.
British Prime Minister David Cameron and Parliament will receive a report after the committee's deliberations, he said, adding that some elements of the report may be redacted on national security grounds for public viewing.
On Monday, a 50-year-old man became the tenth suspect and was detained in Welling, east of London, on suspicion of conspiring to murder 25-year-old soldier Lee Rigby, Scotland Yard said.
Police gave no further information about the suspect's identity.
The two main suspects, Michael Adebolajo, 28, and Michael Adebowale, 22, are still under armed guard in separate London hospitals.
Four other men and the suspect arrested Monday remain in custody at a London police station, while one other man has been released on bail.
Two women were released without charge in the case.
British officials say the two main suspects had been known to them for some time, but revelations that Adebolajo had been arrested in Kenya in 2010 and claims that British security officials had tried to recruit him as an informer after that have fuelled questions about whether UK authorities could have done more to prevent last week's killing.
Far-right protesters marched through the streets of central London on Monday chanting anti-Muslim slogans as part of the backlash of the killing of a British soldier last week.
Police arrested 13 people, mostly on suspicion of causing public disorder.
Anti-Islamic sentiment has been spreading throughout the UK since the attack.
About 1,000 protesters, spurred on by leaders of the far-right English Defence League, gathered in London shouting slogans such as "Muslim killers, off our streets."
In the tense, but largely peaceful demonstration, marchers rallied outside Prime Minister David Cameron's residence waving placards and shouting anti-Islamic obscenities.
"Islamic extremism is probably the number one threat to Britain," one protester, Ben Gates, said.
Since Rigby's death, mosques have been attacked and two men were arrested overnight on Sunday for throwing firebombs at an Islamic cultural centre in Grimsby, in the northeast of England.
Faith Matters, a charity working to defuse religious tensions, said it had registered a spike in reports of Islamophobic attacks in calls to its hotline, describing incidents as "very focused, very aggressive attacks".
Nearly 2,000 people marched at a similar demonstration in the northern city of Newcastle on Saturday.
As anti-racist groups warned there could be more reprisals, Cameron came under intense pressure on Monday for going on holiday, with pictures of him relaxing in Ibiza prompting newspapers to question his leadership at a time of unease.
Two war memorials in London were vandalised with red graffiti overnight, including the word "Islam" spray-painted onto one monument.
In an attempt to counter the right-wing rally, anti-fascist group Unite Against Racism held its own demonstration nearby but was heavily outnumbered by EDL protesters.
A handful of far-right demonstrators threw bottles and coins at the anti-fascist rally. Police vans and officers blocked the two groups from approaching each other.
"They are a minority and a very scary growing minority," an anti-EDL protester who gave her name as Clara said. "I feel ashamed to be a Londoner today. This is disgusting."