France and Britain have both confirmed for the first time that chemical arms were used in Syria and Paris says a line has been crossed. So what next in a conflict that has cost over 94,000 lives?

Not much, experts predict, amid resistance from Syria allies Russia and China and ahead of a proposed peace conference, coupled with painful memories of the Iraq war, which was justified by supposed evidence of weapons of mass destruction that never materialized.

Former British prime minister Tony Blair warned Sunday that the Islamist ideology allegedly behind the murder of a British soldier in a London street was "profound and dangerous".

Blair, now an international Middle East peace envoy, said it was time to admit the breadth of a "strain within Islam" harboring views incompatible with liberal societies.

Russia has blocked a draft United Nations Security Council declaration on the situation in the besieged Syrian town of Qusayr, diplomats said Sunday.

The text, proposed by Britain on Saturday, expressed the council's "grave concern" about the fate of civilians trapped in the strategically important town in central Homs province, where regime forces backed by Hizbullah began an assault two weeks ago.

British counter-terrorism police on Saturday charged a second Muslim convert with murder over the brutal hacking to death of a soldier on a London street.

Michael Adebolajo, 28, has been charged with the murder of 25-year-old soldier Lee Rigby as well as the attempted murder of two police officers and possession of a firearm, London's Metropolitan Police said.

Dozens of people were arrested in London on Saturday as rival far-right and anti-fascist groups faced off over the murder of a British soldier by suspected Islamists.

London's Metropolitan Police said 58 people from the Unite Against Fascism pressure group were arrested after they gathered to oppose a rally by the far-right British National Party (BNP) near the Houses of Parliament.

Two men arrested on suspicion of being involved in supplying illegal firearms in connection with the Islamist murder of a British soldier were released on bail Saturday.

The two unnamed men, aged 46 and 42, were arrested on Friday. They have been bailed to return to a south London police station in late June, pending further inquiries.

The second suspect in the murder of a British soldier in London last week was released from hospital on Friday and taken into custody, Scotland Yard said.

Michael Adebolajo, 28, who was shot and injured by police in the incident on May 22, faces questioning over the killing of Lee Rigby and the attempted murder of a police officer, the force said in a statement.

A British national has been killed in Syria, the Foreign Office confirmed on Friday, after a monitoring group said that Syrian soldiers killed three westerners.

"We understand that a British national has been killed in Syria. Their family have been informed and we are providing consular assistance," a Foreign Office spokesman said.

British police arrested two men on a Pakistan International Airlines plane after fighter jets were scrambled to escort it to a London airport on Friday following an "incident".

Police said the men were detained on suspicion of endangering an aircraft after the plane, which was carrying 300 passengers from the Pakistani city of Lahore to Manchester in northwest England, was diverted to Stansted airport outside London.

U.S. President Barack Obama on Thursday condemned the killing of a British soldier in London by two suspected Islamic extremists as "appalling" and "horrific."

"The United States stands resolute with the United Kingdom, our ally and friend, against violent extremism and terror," Obama said in a written statement.