Obama's US hostage pledge: 'We will not give up'

US President Barack Obama has announced a change in the policy towards hostage-taking, allowing families to pay ransoms without fear of prosecution.

He said the horror and cruelty faced by Americans held hostage abroad meant the previous policy of no concessions had to evolve.

And President Obama said the US would take all measures to get its citizens back, and punish their captors.

''My message to every American being held unjustly around the world.. is that the United States of America will never stop working to reunite you with your family,'' he said.

''We will not give up, no matter how long it takes.''