Congo’s security forces have detained a US diplomat in a raid that also targeted journalists and democracy activists and accused them of posing a threat to stability, a government spokesman said.

The diplomat “was found among a group of people that was believed to be in the process of bringing an attack against state security”, said Lambert Mende. He did not disclose the diplomat’s name or position.

The US embassy in Kinshasa did not respond to messages seeking comment. The State Department did not offer additional information when contacted on Sunday night.

The detentions followed a news conference in Kinshasa organised in support of a Congolese movement known as Filimbi that aims for greater youth participation in politics.

Mende did not say how many people were detained. He said the group was held for identification and investigation, and that foreign journalists had been released. He did not have information on whether the diplomat, activists or local journalists had been freed.

The activists included members of Burkina Faso’s Balai Citoyen and Senegal’s Y’en a Marre movements. Both have led large-scale protests in recent years against presidents attempting to extend their time in office.

In 2011 and 2012, Y’en a Marre mobilised against the re-election bid of Senegal’s then-president, Abdoulaye Wade, who ultimately lost to current president Macky Sall. Balai Citoyen proved instrumental in the popular uprising that led to Burkina Faso ex-president Blaise Compaore’s fall from power in October after 27 years in office.

The leader of Balai Citoyen, Serge Bambara, speculated that the detentions could be linked to the current political situation in Congo.

In January, mass protests erupted in Congo against proposed changes to the electoral law that were widely seen as an attempt by President Joseph Kabila to prolong his time in power. Human Rights Watch reported that at least 40 people were killed in Kinshasa and the eastern city of Goma.