China, Russia and Iran pose three of the biggest threats to the UK in a fast-changing, unstable world, the head of Britain's foreign intelligence agency said Tuesday.

MI6 chief Richard Moore said the three countries and international terrorism make up the "big four" security issues confronting Britain's spies.

In his first public speech since becoming head of the Secret Intelligence Service in October 2020, Moore said China was the agency's single greatest priority as Beijing increasingly backs "bold and decisive action" to further its interests.

Moore said Iran also poses a major threat, and uses the political and militant group Hezbollah - "a state within a state" to fuel political turmoil in Lebanon and other neighboring countries.

He argued that Britain's spies must give up some of their deep-rooted secrecy and seek help from technology firms to win a cybersecurity arms race that is giving hostile countries and groups ever more capacity.

Moore said working with the private sector is a "sea change" for an organization enmeshed in secrecy. Until 1992, Britain's government refused to confirm the existence of MI6.

Report by AP