British forces have already carried out four combat sorties over Iraq using two Tornado jets, that carried out their first mission from Akrotiri on Saturday.
According to the BBC on Monday, none of the missions carried out air strikes on Islamic State positions.
The Cyprus News Agency said a fifth sortie had begun on Monday morning. The fourth operation had taken place overnight on Sunday.
Driving out Islamic State (IS) militants would not be a “weekend campaign”, British Defence Secretary Michael Fallon warned on Sunday.
Fallon said such operations could continue for weeks or even months. “This is not a weekend campaign,” he told BBC Radio 4’s The World This Weekend. “This is going to take a long time.”
The British parliament voted on Friday to join the US-led coalition targeting Islamic State positions in Iraq.
Cypriot Justice Minister Ionas Nicolaou was quoted on Monday as saying that all necessary measures were being taken to up security on the island in the wake of the British military missions from the island.