Orange Order leaders have said there can be no return of the Stormont Assembly until the post-Brexit Northern Ireland Protocol is scrapped.
Marching bands from Orange lodges have been parading through villages, towns and cities in Northern Ireland as part of the traditional Twelfth of July celebrations.
Participants also heard platform speeches between the outward and homecoming parades, with many emphasising unionist opposition to the protocol.
Read more: LIVE updates as thousands take to the streets for The Twelfth parades
The Stormont Assembly has been collapsed for several months while the DUP refuses to nominate ministers to a new Executive until the UK government takes action on the protocol.
Unionists oppose the post-Brexit trading arrangements which demand checks on goods arriving into Northern Ireland from Great Britain, condemning it as a border in the Irish Sea.
Legislation which would give the UK Government the power to override the Brexit deal it signed with the European Union is currently passing through Westminster.
Orange Order Grand Secretary Mervyn Gibson told a Twelfth demonstration in Newry, Co Down, that relations between Northern Ireland and the Republic are at their "lowest point in many years" due to the protocol.
He said: "The Republic of Ireland needs to decide - do they want good relations with the unionist community in all parts of the United Kingdom or do they want to cling to the protocol which damages our economy and denies us sovereignty over our own affairs?
"Micheal Martin - you cannot have both. Micheal Martin - you decide. Do you want to move forward and rebuild relationships, or take us back to a time of cross-border boycotts and tension? An Irish cold war of your making."
Rev Gibson said the next Prime Minister needed to stand firm on the union.
He said: "To help focus his or her mind, we support those unionist elected representatives who have promised there will be no return to the Northern Ireland Assembly until there is a clear, irreversible process that rids us of this treacherous protocol.
"The sooner this happens the sooner we can return to a devolved administration and start building a better Northern Ireland for all its citizens."
The Orange Order Grand Master Edward Stevenson told a demonstration in Bushmills, Co Antrim that the loyal orders had been instrumental in bringing unionist leaders together in opposition to the protocol.
He said: "I, along with my fellow Grand Lodge officers, have held many meetings with the unionist leaders which ultimately delivered the anti-Protocol Declaration.
"All unionist parties signed up to the declaration and (I) call on them all to maintain their firm opposition.
"The only way we can stand strong is if unionists stand together, work together and co-operate on matters of major significance such as the protocol."
He added: "At present we are paying close attention to the progress of the UK Government's Northern Ireland Protocol Bill.
"While it does not provide the answer to all our problems, it must be viewed as a step in the right direction."
Read next:
- The Twelfth: Eleventh Night bonfires lit across Northern Ireland
- Twelfth of July Belfast: Full list of road closures and times for parades
- John Steele: Funeral details for man who died in fatal fall at Larne bonfire
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