A soldier hacked to death on the streets of London has been named as 25-year-old Drummer Lee Rigby, who served in Afghanistan in 2009, Britain's Ministry of Defence said.
"An extremely popular and witty soldier, Drummer Rigby was a larger than life personality within the Corps of Drums and was well known, liked and respected across the Second Fusiliers" a statement from the ministry said.
The announcement came as reports on Thursday said police have arrested a man and a woman, both aged 29, on conspiracy to murder, and as several addresses in Britain were searched.
"This is a large, complex and fast-moving investigation which continues to develop," London police said in a statement. "Many lines of inquiry are being followed by detectives and the investigation is progressing well."
Detectives said they were searching six houses; three in Greenwich in south London, one in Romford, east London, one in north London, and a property in Lincoln in central England.
Meanwhile, Rigby's two main suspected attackers were in separate hospitals being treated for gun shot wounds. They were fired at by officers at the scene of the killing on Wednesday.
They had been known to security services before the attack, reports said.
Al Jazeera's Rory Challands, reporting from London's Scotland Yard, said: "Police have said 'yes, these two [suspects] had cropped up in previous intelligence-gathering probes', but they hadn't proven to be of sufficient suspicion to be investigated any further."
London deployed more than 1,200 extra police officers on the capital's streets amid fears of a backlash on British Muslims.
This action was a betrayal of Islam and the Muslim communities that give so much to our country ... we will not rest until we know every detail.
The attackers had made references to Islam in amateur footage broadcast on television.
The government is "making this gesture to calm down people's fears," said our correspondent. "People are shocked and scared from what they saw, but the government wants to make sure that there is no blame attributed to minorities. These extra police are on streets to reassure people."
Footage broadcast by Britain's ITV news channel showed a man, with hands soaked in blood and holding a meat cleaver and a knife, claiming that he had, motivated by Britain's foreign policy, killed a soldier.
That man is believed to be 28-year old Londoner Michael Adebolajo, who is of Nigerian descent, and is said to have converted to Islam 10 years ago.
Witnesses said he requested to be filmed by a passerby and shouted "Allahu Akbar" during the killing.
In the amateur video, he said: "I apologise that women had to witness this today but in our lands, our women have to see the same ... you people will never be safe. Remove your government, they don't care about you."
The second attacker is believed to be 22 years old. Neither are reported to be in life-threatening conditions in hospital.
Later on Thursday, President Barack Obama offered his support to Britain saying the US "stands resolute with the United Kingdom, our ally and friend, against violent extremism and terror," in a statement.
"I look forward to my trip to the United Kingdom to participate in the June G-8 Summit, hosted by Prime Minister Cameron, which will include discussions on the important global security challenges our countries face together."
After a second meeting of the government's emergency COBRA security council on Thursday, Cameron said the country would "defeat violent extremism by standing together".
|UK's Woolwich reacts to killing of soldier
"This action was a betrayal of Islam and the Muslim communities that give so much to our country ... we will not rest until we know every detail."
Cameron also praised the actions of Ingrid Loyau-Kennett, a cub scout leader who confronted the attackers immediately after the violence and tried to talk them down.
"They told her they wanted to start a war in London and she replied, 'you are going to lose, it is you against many," Cameron said. "She speaks for all of us."
Al Jazeera's Laurence Lee, reporting from Woolwich, said it was essential that political and religious leaders restore calm in the face of violence from the UK's far-right.
"The English Defence League wanted to use this to their advantage. They came out last night chanting 'no surrender to Muslims,' and clashed with riot police," our correspondent said.
Police in the county of Kent, south of London, said they had charged a man with "religiously aggravated criminal damage and burglary" to a mosque.
The Muslim Council of Britain condemned the Woolwich attack, saying: "This is a truly barbaric act that has no basis in Islam and we condemn this unreservedly."
Source: Al Jazeera and agencies