In an update to its travel advice, the FCO said the Moroccan authorities have warned of an increased threat linked to the number of Moroccans sympathetic or belonging to Daesh, formerly referred to as ISIL, and other extremists groups.
Four individuals have been arrested in connection to the murders of the two Scandinavian tourists, who were killed while hiking in the High Atlas mountains.
Moroccan authorities regularly report the disruption of terrorist cells across the country, some of which have intended to carry out attacks in Morocco against government installations, public spaces and tourist sites, said the FCO.
It added: “Attacks could be indiscriminate or target foreigners. In April 2011, 17 people were killed and 25 injured in a large explosion caused by a bomb in Marrakech at the Argana Restaurant in Djema el-Fna Square.
“Protective security measures, including security personnel, may be visible in certain areas including hotels and sites popular with tourists.”