In a rare public speech setting out the major threats to the United Kingdom, Ken McCallum argued that hostile states, radicalized individuals, and a revived Islamic State group have combined to create “the most complex and interconnected threat environment we’ve ever seen.

The head of Britain’s domestic security service said Russia’s military intelligence service was pursuing “dangerous actions conducted with increasing recklessness.”

Threats to the UK from Russia and Iran and the danger posed by the Islamic State group have increased in recent months, according to the head of Britain’s domestic spy agency.