The UK should spend more cash on special forces and aerial drones to combat the threat of so-called Islamic State militants, David Cameron has told defence chiefs.
The Prime Minister has urged the military's high command to look at increasing funding for the SAS and other specialist counter-terror capablilties as part of the upcoming Strategic Defence Review.
The top brass have also been asked to consider new spy aircraft - including drones - to gather intelligence on militant groups like IS.
The Prime Minister wants the SDSR, due to conclude in the autumn, to prioritise resources that will help to protect the UK from evolving threats - not only terrorism and extremism but also an increasingly aggressive Russia and the risks posed by cyber attacks.
The defence chiefs were told of the Prime Minister's priorities last week in a meeting following the Budget commitment to continue meeting the Nato target of spending 2% of GDP on defence.
Mr Cameron said:
The review will also examine how the Royal Navy can work with partners such as the United States to use the new aircraft carrier HMS Queen Elizabeth to deploy drones and special forces against terrorists.
The vessel is due to enter service in 2020 and Mr Cameron will welcome some of the ship's company to Downing Street today.
The Prime Minister will also visit RAF Waddington, the UK's drone base in Lincolnshire, from where operators fly unmanned aircraft over Iraq and Syria.
The RAF's jets and drones are part of the coalition attacking IS in Iraq, but in Syria the drones are limited to a surveillance role - although ministers have begun setting out the case to extend the bombing campaign to the terror group's strongholds in that country.