LONDON

in the wake of the murder of a British aid worker, Britain's prime minister has spoken of his determination to "drive back, dismantle and ultimately destroy" a militant group which has brutally taken over swathes of Iraq and Syria.

"We must recognize that it will take time to eradicate a threat like this," David Cameron told a meeting of advisers, officials and intelligence chiefs Sunday. "It will require... action at home and abroad. We will hunt down those responsible and bring them to justice no matter how long it takes."

A video showing aid worker David Haines' murder was uploaded to the internet by Islamic State of Iraq and Levant (ISIL) militants on Saturday night.

The executioner stated that ISIL was holding Cameron responsible for Haine's death, because of his decision to arm peshmerga (Kurdish forces). 

It also threatened to kill a second British man it is holding hostage, Alan Henning.

"They are killing and slaughtering thousands of people - Christians, Muslims, minorities across Iraq and Syria, Cameron said in a statement released after the meeting Sunday. "They boast of their brutality. They claim to do this in the name of Islam."

"That is nonsense," he stated. "Islam is a religion of peace. They are not Muslims, they are monsters."

Haines was working for a French aid agency in Syria when he was kidnapped in March 2013, while Henning - a fellow humanitarian worker - is believed to have been abducted around December by ISIL in Al-Dana, northern Syria.

For months the ISIL has run riot in large swathes of land in both Iraq and Syria. The U.S. has recently, however, led efforts to form a regional and international coalition to fight the threat posed by the group, the U.K. donating heavy machine guns and ammunition to Iraqi authorities in the fight.

Cameron on Sunday announced a five-point plan to combat what he termed "this menace."

"First, we will work with the Iraqi government to ensure it represents all of its people and is able to tackle this threat effectively," he said.

The plan will involve supporting the Kurdish regional government, who Cameron described as "holding the front line against ISIL."

"We will help them protect their own people and the minorities, including Christians that they have helped already, through our supplies of ammunition and of training."

Cameron said the second point of action would be to work at the United Nations to mobilize the broadest possible support to bear down on ISIL, and the third would be to support the United States in taking direct military action.

"We support that. British Tornadoes and surveillance aircraft have been helping with intelligence gathering and logistics," he added. He underlined, however, that the mission was not about putting British combat troops on the ground, rather about "working with others to extinguish this terrorist threat."

The fourth point of action would be to support humanitarian efforts in Iraq - "including using the RAF [Britain's air force] to do so" - and the fifth - "perhaps most important," said Cameron - would be to reinforce "Britain’s counter-terrorist effort," to prevent attacks and "hunt down those who are planning any."

"It falls to the government, and to each and every one of us to drain this poison from our society," underlined Cameron, "and to take on this warped ideology that is radicalizing some of our young people."

He stated that this is not something Britain can do on its own, "we have to work with the rest of the world."

Saturday's video - which runs for almost 2 1/2 minutes - is titled “A Message to the Allies of America.”

As was the case in previous videos that showed the brutal murders of U.S. journalists James Foley and Steven Sotloff it shows the victim decrying his government’s actions against ISIL.

Haines says: “You [David Cameron] entered voluntarily into a coalition with the United States against the Islamic State just as your predecessor Tony Blair did following a trend amongst our British prime ministers who can't find the courage to say no to the Americans.”

"Unfortunately it is we - the British public - that in the end will pay the price for our parliament's selfish decisions," he adds. 

The executioner - who appears to be the same man seen in the previous videos - says, in what appears to be a British accent, that the UK's alliance with the U.S. will only “accelerate your destruction” and drag the British people into “another bloody and unwinnable war.”

Britain has been trying to identify the man, to determine if he is indeed a British citizen.

www.aa.com.tr/en