(Adds quote, details on Bisha mine)
By Tom Miles
GENEVA, June 8 (Reuters) - Eritrea may have committed crimes against humanity, a year-long U.N. human rights inquiry said in a report published on Monday describing extrajudicial killings, widespread torture, sexual slavery and enforced labour.
"The commission finds that systematic, widespread and gross human rights violations have been and are being committed in Eritrea under the authority of the Government," the 484-page report of the U.N. Commission of Inquiry said.
Slavery-like practices are routine and torture is so widespread that the commission said it could only conclude that the government's policy was to encourage its use.
The commission said it asked Eritrea for access and information during its inquiry but "received no response."
Reuters was unable to immediately reach Eritrean officials for comment.
One of the commissioners said the commission's mandate did not extend to "international crimes" so it could not confirm that Eritrea had committed crimes against humanity or recommend referral to the International Criminal Court.
It would be up to a U.N. Human Rights Council meeting later this month to decide on any further steps, the commissioner, Sheila Keetharuth, said.
Eritrea effectively enslaves people by a system known as "national service" that involves "arbitrary detention, torture, sexual torture, forced labour, absence of leave", the report said.
National service is supposed to last 18 months, but the commission spoke to one witness who had fled after 17 years. Witnesses reported people being executed for trying to avoid being drafted into service as recently as 2013, it said.
The commission said it had evidence forced labour had been used in the construction of the Bisha mine, a copper-gold project owned jointly by Canadian miner Nevsun Resources Ltd and Eritrea.
Nevsun could not immediately be reached for comment. In 2013, in response to similar allegations, Nevsun said it regretted if a state-controlled subcontractor it had been required to use had employed conscripts.
Eritrea maintains a vast detention network and regards anyone who tries to leave the country as a traitor. About 6 percent to 10 percent of Eritreans are now registered as refugees by the U.N.
Eritrea has operated a shoot-to-kill policy on its borders to stop people fleeing. The commission said people were still being shot in 2014, including children. The government says it has ended the policy.
The government operates a "pervasive" surveillance network, while judges are not competent to ensure fundamental rights are upheld, the report said.
Mass killings had also been perpetrated against certain ethnic groups, it added.
(Additional reporting by Edmund Blair in Nairobi and Nicole Mordant in Vancouver; Editing by Tom Heneghan, Jeffrey Hodgson and Leslie Adler)