China is censoring media reports and online discussion on Pyongyang’s latest nuclear test, as it seeks to allay fears over North Korea and maintain stability.

Authorities have blocked searches for the word “hydrogen bomb” and reportedly issued an order for all local media outlets not to “hype” up stories on Sunday’s test.

When Kim Jong-un staged two nuclear tests last year, online reports appeared describing people running and hiding in panic.

However, in the wake of this week’s test, only reports from citing official media describing the facts of the explosion, along with statements from authorities, can be found on the Chinese Internet via the keywords “North Korea nuclear”.

Discussion among China’s 730 million-strong Internet users is also been tightly controlled, according to websites which monitor content on social media. Alarmist or controversial posts have been deleted, they say.

China regularly instructs local media who are reporting on big or sensitive topics to use content from official state-controlled outlets, such as Xinhua news agency.

However, this week’s heavy crackdown suggests growing concern among leaders in Beijing over issues which could spark instability and dissent in the run up to a sensitive political gathering next month – the Congress of the ruling Communist Party.

Efforts to stifle reports on the nuclear test are also thought to be motivated by authorities seeking to shift focus onto the Brics summit of nations, which is being held in the south-eastern city of Xiamen.

Beijing is staging a heavy propaganda push for the conference as it seeks to burnish the global leadership credentials of Xi Jinping, the Chinese president, who has welcomed the leaders of Russia, India, Brazil and South Africa to the meeting.