Nigeria’s government threatened to crack down on unidentified entities it said are seeking to destabilize Africa’s biggest oil producer.

The groups, headed by “disgruntled leaders,” are working to wreak havoc on the government and Nigeria’s existence as a nation state, the presidency said in an emailed statement Tuesday.

“The only accepted way to change a democratically elected government is through elections,” Femi Adesina, senior special adviser to President Muhammadu Buhari, said in the statement. “Any other way is patently illegal, and even treasonable. Of course, such would attract the necessary consequences.”

Africa’s most-populous country is contending with a decade-long war against Islamist insurgents in northeastern Nigeria, a worsening conflict between nomadic herders and crop farmers in the central regions, and a separatist rebellion in the southeast. It’s also facing a growing number of abductions of students that have shut down hundreds of schools.

“The presidency, already vested with mandate and authority by Nigerians till 2023, pledges to keep the country together, even if some unruly feathers would be ruffled in the process,” Adesina said.