The organisers of a loyalist rally at the Ulster Hall have said that they staged the event in the hope of returning the maximum number of unionist MPs in Thursday's General Election.
In a statement on Sunday, organisers said the aim of the event was to motivate loyalists to vote unionist on December 12.
Unionist candidates won 11 of Northern Ireland's 18 seats at the last General Election in 2017.
The rally was styled as a rejection of Prime Minister Boris Johnson's Brexit withdrawal deal, described by loyalists as a 'Betrayal Act' as it would see Northern Ireland treated differently than the rest of the UK.
It has been claimed that the deal would create a trade border in the Irish Sea and leave Northern Ireland tied to the European Union indefinitely.
Some loyalists have claimed the deal would result in an "economic united Ireland".
A series of protest meetings have taken place across Northern Ireland to garner support for resisting the Prime Minister's deal.
Organisers said that the event "also sought to politicise and encourage a younger and more diverse generation of Unionists to speak out in defence of Unionist views and values".
"The overwhelming message of the evening was unambiguous. This generation of Loyalists will not be the generation to fail Ulster," the statement read.
"We will not tolerate an Economic United Ireland. We will not accept a border in the Irish Sea. We will vote Unionist on the 12th December. We will resist the Betrayal Act."
Around 1000 loyalists attended the event, where the Union flag was flown upside, because an upside down Union flag is a recognised sign of distress.
"Ulster is in distress," the rally was told.
The event included performances from the Mourne Young Defenders Flute Band accompanied by pipers and Lambeg drummers.
Among the speakers were a retired Parachute Regiment soldier, a Queen's University Student, a community worker and a Belfast teacher.
It also included historical dramatisations with actors taking on the roles of Robert Quigg, Lady Londonderry, Lord Carson and Private Graham.
The event also heard messages of support from representatives of the Orange Order and Apprentice Boys Of Derry in Scotland, before hearing DUP candidate Nigel Dodds and TUV leader Jim Allister giving "their perspectives on the current political crisis", according to the statement from the organisers.
Senior Orangeman Mervyn Gibson, loyalist blogger Jamie Bryson and Jayda Fransen, former deputy leader of far-right group Britain First, were also in attendance.
A small union flag was placed on every seat in the Ulster Hall for attendees to wave, with the balconies dressed with a number of unionist flag banners.