Nigeria on Monday charged 10 people with treason and conspiring to incite the military to mutiny following last month's nationwide demonstrations that saw thousands take to the streets to protest against a cost of living crisis.

The protests were met with a deadly crackdown by security forces and Amnesty International said at least 13 people were killed. Security forces denied using lethal force.

The 10 men were arraigned in the Abuja Federal High Court and entered a not guilty plea. They face the death penalty if convicted, human rights lawyer Inibehe Effiong said.

State prosecutors said in court papers seen by Reuters that the protesters intended to destabilise Nigeria and "conspired together to commit felony to wit, treason".

Prosecutors also laid five other charges against the accused under the country's penal code, including inciting the military to mutiny, burning government buildings and disturbing public peace.

Lawyers for the protesters sought their release on bail, which was opposed by the state. The court will make a ruling on Sept. 11 when their trial is expected to begin.

Amnesty urged the government to unconditionally release all the people arrested during the protests. It said the trial was meant to unlawfully justify detaining protesters.

"These are blatantly trumped-up charges that must be immediately withdrawn," said Isa Sanusi, director for Amnesty International Nigeria.

Nigerians blame economic reforms by President Bola Tinubu, in office since May 2023, for economic hardship, worsened by double-digit inflation after the currency was devalued and the cost of petrol and electricity rose.