CLEVELAND (AFP) - The north-eastern US city of Cleveland insists it is prepared for the Republican National Convention, but on the eve of its biggest political moment in decades, it is bracing for protests that may well disrupt proceedings.
Several organised events opposed to Donald Trump, the brash billionaire set to become the Republican Party's 2016 presidential nominee, will take place Sunday even as authorities drape a heavy security blanket over the city of 400,000 people.
Thousands of police from Ohio and dozens of other jurisdictions across the country, including federal officers and agents, will be in place for the July 18-21 convention.
But their presence was already felt on Saturday. Tall fencing measuring 2.5-m high was erected around the Quicken Loans Arena, forming a hard buffer between the convention site and the public. Several roads were already closed off, while others are lined with concrete barriers.
Helicopters patrolled above the city, their side doors open so security forces could better scan for disruptions below.
A downtown demonstration advertised as a "march against racism, Islamophobia, attacks on immigrants and on LGBTQ people and endless war" is expected to draw 1,000 people or more on Sunday.
A potentially larger "Stop Trump" march has been permitted by the city for noon on Monday, just hours before the convention kicks off.
Anti-war activist Tom Burke, a spokesman for the 40-group anti-Trump coalition that is convening on Cleveland, said he expects the events to be peaceful.
But "there will be agitation in that we have a political message that the Republicans are not going to like," he told AFP.
"Trump promotes hate, he promotes racist attacks on people." Protesters have pressed the city for months for permission to march right up to the convention. The Coalition to Stop Trump and March on the RNC says it has been given permission to march Monday up to the "vicinity" of the arena.
In testimony before Congress this week, Homeland Security Secretary Jeh Johnson acknowledged he was "concerned about the prospect of demonstrations getting out of hand" in Cleveland, and at the Democratic National Convention the following week in Philadelphia.
He said some 3,000 federal personnel will be deployed to help protect attendees and maintain order at the conventions.
US authorities have been on alert since a gunman intent on killing white policemen went on a rampage and shot five Dallas officers dead.
A string of terrorist attacks in Orlando and San Bernardino, as well as the horrific attack in the French city of Nice that left 84 people dead, have also left cities on edge.
Complicating security matters is the fact that Ohio is an open carry state, meaning members of the public can legally carry their firearms into downtown Cleveland during protests.
The Southern Poverty Law Center, which tracks extremist groups, said the Oath Keepers will be present in Cleveland. It's a group of current and former members of the military who appear at events armed.
On Saturday, black power activists including the New Black Panther Party staged a small demonstration in Cleveland, chanting "No justice, no peace" and demanding better police treatment of African Americans.