Britain has pledged to contribute 1,000 military personnel to a proposed NATO force that could be deployed anywhere in two-five days, BBC reported Friday.

Speaking on the second day of the NATO summit in the Welsh city of Newport, British Prime Minister David Cameron said the “multinational spearhead force” would be part of a reformed NATO response force with headquarters in Poland.

Downing Street later said the force would comprise of 4,000 troops, be led by a British general and would be ready for deployment by the end of 2015.

The British prime minister also warned about the threat imposed by the Sunni extremist group Islamic State (IS).

“We face new and evolving dangers,” Cameron said.

The IS has threatened to kill British aid worker David Haines, who was kidnapped in Syria in March 2013. The militant group made the threat through a video showing the beheading of US journalist Steven Sotloff.

“They should be very clear these terrorists that their threats will only harden our resolve to stand up for our values and to defeat them,” he said.