A Foreign Office minister will visit Nigeria today for talks on how the UK can help find hundreds of girls abducted from their school a month ago.
Mark Simmonds will hold high-level meetings amid suggestions that UK drones and other surveillance assets could be used in the hunt.
Downing Street said earlier that David Cameron had watched footage released by Boko Haram militants of around 130 captives, and it had underlined to him the "pure evil" of the crime.
A British team including counter-terrorism and intelligence experts is in already in Abuja, and the US is among a host of other countries contributing to the effort.
Mr Simmonds, Minister for Africa, said: "This is an horrific and heartbreaking situation and the UK wants to do all it can to offer support to the Nigerian efforts to secure the release of the kidnapped girls."
According to reports, the search is closing in on a forest near the border with Cameroon and the girls have been divided into at least four groups.