Obama announced new "presidential policy guidelines" on the standards his administration uses when deciding to launch drone strikes.

NPR: Obama Sees Narrower Terror Threat, Defends Drones

Several Nato members, including the US and France, say they will help to train an African force for the Mali operation, but have not offered to send ground troops or launch air strikes.

BBC: Nato forces needed in Mali, says AU's Thomas Boni Yayi

Obama announced new "presidential policy guidelines" last week on the standards his administration has been using when deciding to launch lethal strikes, including a guideline to strike a target only if it presents an "imminent threat" to U.S. national security and only if the target cannot be captured.

NPR: Drone Strike Comes Despite Transparency Pledge

Pest managers could therefore encourage people to launch pre-emptive strikes against them by organising intensive trapping campaigns at the right moment.

ECONOMIST: Pest control

The United States rejects the North's claim that such a deterrent is necessary, saying it does not intend to launch pre-emptive strikes against North Korea.

NPR: Despite Threats, Risks Temper Korea War Tensions

Mr Walsh is right to be fearful, particularly if unions balk at his plans to cut 3, 500 jobs and opt to launch a summer of strikes.

ECONOMIST: Airlines in the recession

Without the ability to launch pre-emptive strikes, the naval vessels must wait until something happens until they can act, and even then they are limited in what they can do.

CNN: How to solve the pirate problem

The US rarely comments on the details of drone strikes in Pakistan, but correspondents say that for many years Islamabad was allowed to launch them from bases within the country.

BBC: Predator B drone (November 2011)