Image copyright Reuters Image caption Hun Sen has been increasing his control over Cambodian media and social media in recent months

Media outlets in Cambodia have been told they must begin referring to PM Hun Sen as "Lord Prime Minister and Supreme Military Commander".

In a three-hour briefing at the information ministry, reporters were told full titles must be used on first reference from August for the PM, the first lady and other officials.

They were also asked why they had not complied with earlier similar requests.

Failure to comply could lead to action, but it was unclear what this would be.

Hun Sen's honorary, six-word title in Khmer, "Samdech Akka Moha Sena Padei Techo Hun Sen", would have to be used in the opening lines of print articles, radio and TV stories about the leader.

The first lady Bun Rany Hun Sen's title would roughly translate to "Celebrated Senior Scholar Bun Rany Hun Sen", the Associated Press news agency reports.

The ministry said it was important to show respect for Cambodia's highest leaders.

Hun Sen, one of the world's longest serving prime ministers and a self-styled strongman, has been trying to exert more control over media and social media recently, often threatening legal action against his critics.

Officials' honorary titles are already widely used by pro-government media outlets, AP reports.