The Council of Europe has condemned the attack on a Roma camp on the outskirts of Lviv in western Ukraine and expects a full and transparent investigation of the incident without delay.

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"We condemn another attack on Roma people, as reported by police today. We are horrified this time one person was killed. We expect a full and transparent investigation without delay," Director of Communications at the Council of Europe, Spokesperson of Secretary General Daniel Holtgen wrote on Twitter.

Seven suspects aged 16 and 17, residents of Lviv, have been arrested, as well as a 20-year-old accused of planning the attack, the police said.

Criminal proceedings were opened under Clause 12, Part 2 of Article 115 (premeditated murder committed by a group of persons upon prior conspiracy) of the Criminal Code of Ukraine.

The attackers may face up to 15 years in prison.