Violent clashes erupted between far-right nationalists and counter-protesters in Charlottesville, Virginia, early Saturday ahead of scheduled a “Unite the Right” rally at the city’s Emancipation Park.

The police declared an unlawful assembly alert.

The clashes came despite police efforts to keep the rival protesters apart following a confrontation late Friday in the University of Virginia’s campus in which counter-protesters claimed they were hit by torches and pepper spray.

Fighting and scuffles breaking out between protesters and demonstrators opposed to the far right; police in riot gear were assembled nearby.

WATCH: White nationalists and counter-protesters clash at Charlottesville rally

Projectiles were thrown between the groups and some of those present could be seen pushing and throwing punches in Emancipation Park.

By 11.15am ET, missiles such as empty bottles were being exchanged at the south-east end of the park. Far-right supporters formed a “Roman tortoise” shield wall at the gate. Counter-protesters cleared when a gas weapon was released.

Shortly later, smoke grenades were launched from the park into the crowd of counter-protesters. On both occasions, those in the street beat a hasty and uncoordinated retreat.

ALERT: Unlawful assembly declared for rally at Emancipation Park #cvilleaug12

Earlier, amid heightened tensions, protesters and counter-protesters had begun arriving in force at the park, where police were supervising the construction of barricades around a 20ft statue of the Confederate general Robert E Lee, which is the focus of the rally, and has been at the centre of other recent confrontations in Charlottesville.

With a police helicopter buzzing overheard, successive groups of mostly young men, carrying Confederate flags, rune banners, “Kekistan” flags and other racist symbols entered via the south-east and south-west ends of the park.

They then passed through gaps left in the barricades surrounding the protest and the Robert E Lee statue which it claims to be defending.

The passage of the far-right groups was watched over by Virginia state police, Charlottesville police officers, and armed “Three Percent” militia members, who were dressed in fatigues and open-carrying automatic weapons.

Facing them on Market Street were counter-protesters, many marching under the red and black banners of antifascist organizations.

The south-east entrance was briefly blocked by a group of about 20 clergy members, including Cornel West, who linked arms across the top of the stairs to the park.

The Rev Seth Wispelwey, of Sojourners United Church of Christ in Charlottesville, said of the group: “We’re here to counteract white supremacy, and to let people know that it is a system of evil and a system of sin.”

Just before 11am, a formation of around 200 people comprising members of the neo-Confederate League of the South, the Traditionalist Workers party and National Socialist Movement were briefly halted by protesters before moving towards the south-east gate. One of their number was seen to mace a young female protester who approached the group.

By the time they made it in, there were well over 500 far right protesters in the park, with around 1,000 counter-protesters in the street.