Mayor Bill de Blasio was due to become the first mayor in decades to sit out New York City’s traditional St Patrick’s Day parade on Monday over a dispute involving whether march participants can carry pro-gay signs. But Ireland’s prime minister said he would join the procession in Manhattan because the holiday is about Irishness, not sexuality.

New York’s Irish, their descendants and the Irish-for-a-day planned to revel in the celebration of culture on Monday, but De Blasio’s decision to skip the parade underscores lingering political tensions over gay rights issues in the north-east US.

Boston’s mayor Martin Walsh opted out of his city’s parade on Sunday after talks broke down that would have allowed a gay veterans group to march. Parade organizers said they did not want the event to turn into a demonstration for a particular group, but Walsh said their plans prevented all Boston residents from participating fully.

Still, thousands of green-clad spectators came out to watch bagpipers and marchers in Boston, and organizers of a float intended to promote diversity threw Mardi Gras-type beads to onlookers. A similar scene played out in downtown Philadelphia.

In Michigan, parades were Sunday held in Bay City and Detroit, and on Monday, a St Patrick’s Day parade was scheduled in Cleveland. Cities from Savannah, Georgia, to Montreal also hosted festivities over the weekend, and throughout the world, landmarks were bathed in green floodlights.

Ireland’s head of government, Enda Kenny, on Sunday became the first Irish prime minister to attend Boston’s annual St Patrick’s Day breakfast.

Kenny has resisted pressure, in both Ireland and America, to support the gay rights lobby’s demand to have equal rights to participate in parades on St Patrick’s Day.

“The St Patrick’s Day parade [in New York] is a parade about our Irishness and not about sexuality, and I would be happy to participate in it,” he said in Dublin before leaving for a six-day trip to the US.

In Ireland, St Patrick’s Day provides the launch of the country’s annual push for tourism, a big part of the rural economy.

“To Irish people by birth or descent, wherever they may be in the world, and to those who simply consider themselves to be friends of Ireland, I wish each and every one of you a happy, peaceful and authentically Irish St. Patrick’s Day,” Irish president Michael D Higgins, the ceremonial head of state and guest of honor at Monday’s parade in Dublin, said in a statement.

Parade organizers in New York have said gay groups are not prohibited from marching, but are not allowed to carry gay-friendly signs or identify themselves as LGBT.

Some LGBT groups were to protest the parade along the parade route on Fifth Avenue on Monday. Others had planned to dump Guinness beer from the shelves of the Stonewall Inn, the birthplace of the gay rights movement, in protest of the brewer’s plan to sponsor the parade, but that demonstration was canceled late Sunday after Guinness said in a statement that it had dropped its sponsorship.

Other beer companies joined the boycotts earlier, with Sam Adams withdrawing its sponsorship of Boston’s parade and Heineken following suit in New York.

New York’s parade, a tradition that predates the city itself, draws more than 1 million spectators and about 200,000 participants every March 17. It has long been a mandatory stop on the city’s political trail, and includes marching bands, traditional Irish dancers and thousands of uniformed city workers.