Cameron calls Cobra meeting

Prime Minister David Cameron confirmed the death of British aid worker David Haines in a statement early on Sunday, after the Foreign Office had earlier said that it was working to verify the authenticity of a video posted on the internet, purportedly showing the Briton being beheaded.

Cameron described the killing of Haines as "a despicable and appalling murder of an innocent aid worker," as well as "an act of pure evil."

"We will do everything in our power to hunt down these murderers and ensure they face justice, however long it takes," the prime minister said.

He also expressed his condolences to the victim's loved ones, saying that "my heart goes out to the family of David Haines who have shown extraordinary courage and fortitude throughout this ordeal."

Cameron was to chair a meeting of the government's Cobra emergency committee on Sunday to discuss how to respond the video.

In the footage, posted on the Internet late on Saturday, a hooded man with a British accent and wielding a knife addresses the UK prime minister directly, saying that a British citizen was paying the price for the country's decision to supply weapons to Kurdish peshmerga forces who are fighting "Islamic State" (IS) extremists in northern Iraq.

The 44-year-old Haines, a former member of the Royal Air Force and father to two children, had worked for various aid agencies in some of the world's most dangerous places, beginning in the former Yugoslavia in 1999. He had been working for the French-based Agency for Technical Cooperation and Development when he was seized by gunmen in northern Syria in March 2013.

His family has paid tribute to his dedication to his humanitarian work.

"David was most alive and enthusiastic in his humanitarian roles," his brother Mike said in a statement released through the Foreign Office.

US support

President Barack Obama issued a statement late on Saturday offering condolences to the family and the British people.

"We will work with the United Kingdom and a broad coalition of nations from the region and around the world to bring the perpetrators of this outrageous act to justice, and to degrade and destroy this threat to the people of our countries, the region and the world," Obama said.

IS extremists have also claimed the beheadings of two US journalists seized in Syria, James Foley and Steven Sotloff.

US Secretary of State John Kerry has been touring the Middle East to put together a coalition to confront the IS, which American fighter jets have been bombing in northern Iraq. On Sunday, Australia to contribute troops to anti-IS coalitionAustralian Prime Minister Tony Abbott announced that his country would send 600 military personnel# to the region.

pfd/sms (AP, AFP,dpa)