After 10:15 p.m police in northern Greece have clashed briefly with extreme left protesters outside an international trade fair where the prime minister is hosting the commerce secretary of the United States.
The protesters dispersed quickly from a square by the Thessaloniki International Exhibition Center. Two other demonstrations — one staged by 6,000 pro-communist unionists and one with about 7,000 participants from other trade unions, ended without incident on Saturday night.
But Greek nationalists opposed to the government's deal to end a name dispute with neighbouring Macedonia remained on Thessaloniki's waterfront.
Police fired tear gas and stun grenades after some of the 6,000 nationalist protesters threw rocks and other objects at officers.
U.S. Commerce Secretary Wilbur Ross spoke at the trade fair before Prime Minister Alexis Tsipras' keynote address on the economy.
Greek police say tear gas and stun grenades have been used to keep thousands of protesters from reaching a venue where Prime Minister Alexis Tsipras is due to give a keynote address on the economy.
The crowd of about 6,000 gathered to protest an agreement Greece signed with neighbouring Macedonia to end their long name dispute.
Officers kept the protesters at bay, but the group approached the fairgrounds from another direction and attacked officers with rocks and others items.
Three more protest marches are headed to the Thessaloniki International Exhibition Centre. Police let about 6,000 participants in a union-backed march by without incident.
U.S. Commerce Secretary Wilbur Ross has inaugurated a trade fair in recession-weary Greece, where the government is pushing for overseas investment but faces mass protests after years of plummeting living standards.
Ross joined Greek Prime Minister Alexis Tsipras Saturday at the opening of the annual trade fair. The United States is the featured country at this year's event, and Ross traveled with a delegation of executives from dozens of major U.S. companies.
Greece last month ended its third consecutive international bailout and now must return to markets that have been rattled by financial concerns in nearby Italy.
Some 4,000 police officers are on duty in the northern Greek city as several major protest rallies are planned, led by labor unions.