Two Swedish journalists who are accused of aiding an outlawed rebel group in Ethiopia pleaded not guilty on Thursday to terrorism charges in Ethiopia's Federal High Court.

Ethiopian troops arrested freelance investigative journalist Martin Schibbye and photojournalist Johan Persson in July with members of the Ogaden National Liberation Front, which Ethiopia considers to be a terrorist group.

The journalists say they were travelling with the rebels to do a story on the drought and malnutrition crisis in parts of Ethiopia.

While Schibbye and Persson pleaded not guilty to the terrorism charges, they did admit to entering the country illegally.

Swedish media have reported that the journalists were investigating alleged human rights violations by Ethiopian troops.

Ethiopia sharply restricts journalists and humanitarian aid workers access to the Ogaden region, which borders Somalia.

The ONLF has been fighting for regional independence from Ethiopia since 1984. The rebels accuse Ethiopia of atrocities against the region's largely ethnic Somali population.

Human rights and aid groups have accused both the ONLF and pro-government forces with numerous rights violations during the conflict, charges both sides have denied.