A protester is detained by riot policemen during clashes at the northern Greek city of Thessaloniki, Saturday, Sept. 8, 2018. Police in northern Greece have clashed with protesters outside an international trade fair where prime minister Tsipras made a keynote speech. (Dimitris Tosidis/Associated Press)

THESSALONIKI, Greece — Police in Greece’s second-largest city say a protest rally that determined nationalists staged near an international trade fair where the prime minister was keynote speaker resulted in eight arrests.

Authorities in Thessaloniki estimated that 6,000 people attended Saturday’s rally opposing Greece’s agreement with neighboring Macedonia to end their long dispute over the latter’s name.

The demonstrators tried to reach the venue for the trade fair. Some threw items at the officers who blocked them, and clashes with police continued late into the night.

Thessaloniki police say 15 officers were injured and the eight people arrested included a minor. They say 20 more people were detained and released.

The police said they had no reports of injuries among the protesters.

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