An evangelical lobby group has hit out at the Belfast City Marathon, which will be held on a Sunday for the first time this year.
The Caleb Foundation said church services will be disrupted and Christian runners who regard Sunday as a special day will be excluded.
This 38th Deep RiverRock Belfast City Marathon will be held on Sunday, May 5.
Starting in the Stormont Estate, it will feature a new flatter, faster route for marathon and team relay participants, finishing in Ormeau Park.
But some are more concerned with the fact that it will be held on a Sunday for the first time.
The Caleb Foundation chairman, Wallace Thompson, said that "like many evangelicals, we were very saddened and perturbed by the decision to change the Belfast Marathon from the May Day Bank Holiday Monday to the Sunday".
"Not only are we concerned about the practical impact this could have on church life in the city on the day, but, more importantly, the day change means that those evangelicals who hold to a high view of the Lord's day will not feel able to participate. As a result, the Belfast Marathon is no longer an inclusive event."
The fundamentalist Protestant organisation has produced a leaflet - Belfast City Marathon: What the Scriptures Have to Say - outlining its position.
The leaflet states: "Christians in the city find themselves in something of a dilemma. Along the marathon route, not a few will be disrupted either going to or coming from Church; many would have wanted to participate, as in previous years, but obedience to Biblical teaching will prevent them from doing so."
Marathon organisers said they had been consulting with those affected by the event to minimise its impact on them. "The Belfast City Marathon management team have undertaken a role of engagement with all relevant stakeholders who could be affected by the new route and have received great support from an array of Churches and denominations across the city," a spokesperson said. "Every effort has been made to minimise disruption on the day.
"The Deep RiverRock Belfast City Marathon is inclusive to all and helps raise more than £1.6m annually for local charities."
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