Iran focused on attacking "harder targets," U.K. spy chief warns

What happened: MI5 chief Ken McCallum said in his annual threat update that Iran made a "major shift" toward attacking harder targets in the UK, including military sites, and that Russia remains "aggressor number one." Key numbers: More than 50 Iran-linked arrests in the UK over the past year. Why it matters: McCallum said Iran uses criminal proxies and subcontracting, making attribution harder, and linked Russia's hybrid warfare to limited military progress in Ukraine. He also warned AI is "supercharging" the cybersecurity contest and could make biological weapons more dangerous.

MI5 chief Ken McCallum said in his annual threat update that Iran made a "major shift" toward attacking harder targets in the UK, including military sites, and that Russia remains "aggressor number one."

McCallum said Iran uses criminal proxies and subcontracting, making attribution harder, and linked Russia's hybrid warfare to limited military progress in Ukraine. He also warned AI is "supercharging" the cybersecurity contest and could make biological weapons more dangerous.