The British prime minister is set to promise to send military helicopters to a French counter-terrorism operation in Mali, reports AFP news agency.
The announcement is expected at a UK-France summit later today.
The three RAF (Royal Air Force) Chinook helicopters would give logistical support to French troops fighting Islamist militants.
It is part of broader counter-terrorism and military efforts there by the UN, the EU and the African Union.
“Recent terrorist attacks across Europe underline the scale of the cross-border challenge we face in keeping our citizens safe,” the UK government spokesman told AFP.
Britain is also expected to promise $69m (£50m) in additional aid for those affected by epidemics, natural disasters and conflict across Mali, Niger, Chad, North Cameroon, Burkina Faso and Mauritania.