The US says has described the abduction of more than 200 girls from a secondary school in Chibok, Borno State, as “an outrage and a terrible tragedy” and has offered to assist the Nigerian government rescue and reunite them with their families.

White House spokesman, Jay Carney, said President Barack Obama receives constant briefs from his national security team monitoring developments and that the State Department has been in regular touch with the Nigerian government about where to come in terms of supporting efforts to find and free the girls.

“We view what has happened there as an outrage and a terrible tragedy,” he said adding that the US was offering counter-terrorism help to Nigerian investigators that involved “information-sharing” and improving Nigeria’s “forensics and investigative capacity”.

Britain is also giving support to the Nigerian government as confirmed by the Foreign Secretary William Hague, who described the kidnap as “disgusting and immoral”.

Leader of the Boko Haram sect, Sheikh Abubakar Shekau, in a new video released Monday, claimed responsibility for the kidnap saying the girls were “spoils of war and no more than slaves” and that he can do with them whatever he likes.

Hague said, “Using girls as the spoils of war and the spoils of terrorism is disgusting and immoral. It should show everybody across the world that they should not give any support for such a vile organisation.”

He said in spite of the assistance from his country, the primary responsibility of finding the girls will rest with Nigerians, and expressed hope that the federal government will do what is necessary to reunite them with their families.

It is 22 days today since the abduction on April 14.