Eritrea’s use of indefinite national conscription is still the main factor spurring thousands of people to flee the Horn of Africa country every month, even after the government said it would scrap the practice, Amnesty International said.

A conscription system established in 1995 requires all adults to perform 18 months of national service, a period that’s “extended indefinitely” for “a significant proportion” of people, the London-based rights group said in a report. Amnesty interviewed people who’d been in service for more than 10 or 15 years before fleeing over the past 18 months, and others with husbands and fathers still conscripted after two decades.

“Conscripts continue to be deployed in a range of civilian as well as military roles,” Amnesty said. “The system therefore continues to amount to forced labor, in violation of international law.”

 Eritreans are the third-biggest group of people risking their lives to cross the Mediterranean, and the United Nations estimated at end-2014 that more than 5,000 left each month. The Eritrean government says national service is necessary for the country’s defense from its southern neighbor, Ethiopia, and has described those fleeing as economic migrants.

Eritrean Information Minister Yemane G. Meskel said Amnesty had “neither the qualifications nor the moral authority” to advise the country on organizing its defenses.

“All those who condone violation of international law and tolerate occupation have no rights whatsoever to accuse Eritrea of prolonged service,” he said on Twitter, in reference to Ethiopia’s presence in Badme, a disputed territory that triggered a 1998-2000 conflict. A UN boundary commission ruled in 2002 that Badme belonged to Eritrea. Ethiopia has rejected that ruling and still occupies the town.