Thousands of Algerians demonstrated Saturday against plans to drill for shale gas in the south of the country.

Organizers say more than 1,000 demonstrators protested in Ouargla, a city 466 miles south of Algiers. Another 1,000 demonstrators participated in a separate protest in In Salah, 785 miles south of Algiers, according to Algeria’s state news agency APS.

The protests were called by a coalition of opposition parties and human rights groups. The peaceful protests concluded with no interference from police, organizers said.

Demonstrations have been ongoing since the beginning of the year against the possible environmental damage related to the exploitation of Algeria’s shale gas reserves.

Algeria announced plans to drill for shale gas in 2014, with an initial test well dug in Ahnet, near In Salah.