Helicopter flight to Panama border camp

Panama is safer than many of its Central American neighbours, with lower murder rates than Honduras, El Salvador and Guatemala.

But there is one area of the country where security is tenuous and the threats to locals' safety are many.

It is the province of Darien, on the border with Colombia.

Once a stronghold of the Colombian left-wing rebel group, Farc, it is now a main corridor for drug traffickers smuggling cocaine from Colombia north to the US.

Here, the Colombian army and the Panamanian border police have built a joint border post called La Union.

BBC News travelled to the post by helicopter.