Runners at the Belfast City Marathon will observe a minute's silence in memory of those killed or injured during the Boston bombing, organisers have said.
More than 17,500 people are expected to take part in the 26.2-mile race on Monday which includes a team relay, fun run and nine-mile walk through all parts of the city.
Three spectators including an eight-year-old boy were killed and more than 250 other people injured when two bombs were detonated near the finish line of the US event earlier this month.
Suspected bomber Tamerlan Tsarnaev, 26, was killed a few days after the attack during a shootout with police.
His younger brother, Dzhokhar Tsarnaev, 19, was captured and charged in connection with the explosions.
Meanwhile, for the first time, a former Olympic gold medallist and world champion is to take part in the Belfast Marathon.
Ethiopian runner Hunde Gezahegne Abere, who took gold at the Sydney Games in 2000 and was world number one a year later, will be up against other top athletes such as Wosen Zeleke Demse, Ashenafi Eshetu Deme and Birhanu Niguse Melese, also from Ethiopia.
The Kenyan trio of Joel Kipsang Kositany, James Rotich and Freddy Sittuk, who finished fifth in Belfast 12 months ago, will also be vying for a place on the podium.
Top challenger in the women's race will be 21-year-old Ethiopian Lemlem Berbe Yachem, who has a personal best of two hours 34 minutes and 38 seconds.
The leading local runner is Irish international Thomas Frazer, from St Malachy's Athletics Club, who will be trying to improve his personal best time of two hours 18 minutes and 37 seconds.