Nigeria's north has been under attack by the radical Islamic sect known as Boko Haram in the last 18 months and foreigners have become increasingly targeted as the violence has grown.
- In May, gunmen in northern state Kaduna killed a Lebanese and Nigerian construction workers while kidnapping another Lebanese employee.
- Later that month, kidnappers shot a German hostage during a rescue operation.
- Authorities said gunmen linked to Boko Haram kidnapped an Italian and British man last year who were later killed during a rescue operation by Nigerian soldiers.
- Chinese construction workers have also been killed by gunmen around Maiduguri, a north-eastern city in Nigeria.
The sect has been blamed for killing at least 729 people in 2012, according to an Associated Press count.
More top news
Bodies are being buried in backyards and overwhelming morgues as officials try to find another plot of land to lay them to rest.
Authorities have warned that the death toll is likely to rise as much of the building is yet to be searched.
The PM will sound out the possibility of new free trade agreements with Gulf states for once the UK has left the EU.