LONDON: British police made two further arrests on Thursday and raided houses across London following the brutal murder of a serving soldier who survived a tour of duty in Afghanistan.

Prime Minister David Cameron appealed for calm after 25-year-old Lee Rigby was butchered outside a London Army barracks on Wednesday, while an extra 1,200 officers were deployed on the capital’s streets in a bid to reassure the public.

The intelligence agencies, meanwhile, came under scrutiny after it emerged that the two murder suspects, who were injured in police gunfire at the scene, had been known to the security services.

Both men, aged 28 and 22, are believed to be Britons of Nigerian origin. One of them had frequented meetings by the now-banned Islamist group Al-Muhajiroun, its UK leader Anjem Choudary said.

The two chief suspects are under arrest in separate hospitals. They are both stable and their injuries are not life threatening, police said.

In a brazen mid-afternoon attack in Woolwich, southeast London, the pair apparently hacked Rigby with knives and a meat cleaver before attempting to explain their actions in an Islamist tirade to passers-by.

The victim, who has a two-year-old son Jake, was a  machine gunner who served with
North Atlantic Treaty Organization-led forces in Afghanistan in 2009, the defense ministry said.

The Sun newspaper on Friday reported that the victim’s girlfriend was herself serving with the Royal Military Police in Afghanistan and was flying home after receiving the news.

Police searched five properties in London and one in a village in eastern England, and announced the arrests of a man and a woman, both aged 29, for conspiracy to murder.

“This is a large, complex and fast-moving investigation which continues to develop,” a spokesman said.

Detectives are sifting through witness statements, social media and security camera footage, while forensic experts have been combing the scene in Woolwich for evidence.

British media are naming      the suspects as 28-year-old Michael Adebolajo and 22-year-old Michael Adebowale, both from London.

Islamist preacher Choudary said Adebolajo was from a Nigerian family, converted to Islam in 2003 and took the name “Mujahid.” He regularly attended sermons by banned Islamist preacher Omar Bakri, the Al-Muhajiroun founder.