Thousands of members of the Royal Black Institution and supporters are taking part in the organisation's annual Last Saturday demonstrations across Northern Ireland.

The parades, which mark the traditional finale of the summer marching season, are being held in five locations, with County Down's flagship demonstration taking place in Newry.

About 17,000 members and supporters are expected to attend events throughout the day, while approximately 300 marching bands are participating in parades and demonstrations.

The event remains one of the most significant dates in the Royal Black Institution's calendar.

The parade in Newry got under way after 12:00 BST.

Demonstrations are also taking place in Larne, Dungannon, Dundonald and Coleraine, attracting participants from across Northern Ireland, the Republic of Ireland and overseas.

Large crowds lined routes as lodges paraded through their respective host towns, ahead of the traditional platform proceedings and religious address, before they make their way back along the return route.

This year's host venues are: Newry (County Down), Larne (County Antrim), Dungannon (Counties Armagh and Tyrone), Dundonald (Belfast area) and Coleraine (County Londonderry).

The Sovereign Grand Master, Rev William Anderson, is expected to address members during the day's proceedings.

Senior officers are also expected to acknowledge the efforts of host committees, volunteers and the hundreds of bandsmen and women taking part in the day's events.

The Royal Black Institution has about 17,000 members. While most are based in Northern Ireland, there are preceptories in Scotland, England, the Republic of Ireland, Canada, Australia and New Zealand.

The institution was founded in Ireland in 1797, two years after the formation of the Orange Order. It describes itself as being based on the teachings of Holy Scripture and committed to the furtherance of the Christian message of the Cross.

Members are known as Sir Knights.

The organisation's two principal annual demonstrations are the Sham Fight on 13 July and the Last Saturday demonstration at the end of August.

Police in Belfast have said there will be an impact on traffic.

Drivers and those not attending are advised to avoid the areas and take an alternative route if possible.

In north Belfast, the parade began at about 9:15 BST at Crumlin Road and proceed to then Carlisle Circus, Clifton Street, Donegall Street, Royal Avenue, Donegall Square and conclude at Linenhall Street.

The parade will travel the same route in return from Linenhall Street beginning at about 17.15.

Another parade began in West Belfast Orange Hall and move along Shankill Road, Peters Hill, North Street and Royal Avenue to York Street. At 17.30 the parade will return via the same route.

In east Belfast, the main parade started at about 9:15 on Templemore Avenue moving along the Newtownards Road, Bridge End, Queens Quay and onto Station Street. The return parade, which begins at 17.30, will follow the same route in reverse.