The Ethiopian’s 2015 victory came two years after he secured his first gold medal, which he returned to the city in a gesture of sympathy following the bombings that claimed the lives of three people and injured more than 260 others close to the finish line.

Desisa has raced in only nine marathons, winning three, and posted a personal best of 2 hours 04min 45sec in Dubai in 2013.

"Everyone comes here to win but with God's help I will win again," said the 26-year-old, who won Boston in 2:09:17 last year.

"My training has been better than it was last year."

Kenyan Wesley Korir, whose personal best is 2:06:13, has been touted for success if it proves to be a warm day.

The 33-year-old is returning to Boston for a fourth time having won in 2012 - the last time the marathon coincided with hot temperatures.

His compatriot Sammy Kitwara ran 2:04:28 at the 2014 Chicago Marathon, making him the fastest in the field by a bare four seconds over Ethiopia’s Tsegaye Mekonnen, whose 2:04:32 came in Dubai the same year.

Joining Mekonnen in the race is fellow Ethiopian Lemi Berhanu Hayle, who registered a personal best of 2:04:33 on his way to finishing second in Dubai in January. 

Kenya's Geoffrey Mutai comes into the marathon with the fastest personal time of 2:03:02, a course record he set with his 2011 victory. 

Stephen Chebogut, also of Kenya, is considered a strong contender having won in Eindhoven last year with a personal best time of 2:05:52.

In the women’s race, defending champion Caroline Rotich of Kenya is likely to face a strong challenge from Tiki Gelana, who is the reigning Olympic champion and can lay claim to the fastest time of the field with a personal best and Ethiopian record of 2:18:58.

Ethiopia’s Buzunesh Deba, a two-time runner-up in New York, is also likely to be in the mix as the owner of the fastest legal time on the Boston course - 2:19:59. 

American Neely Spence Gracey is set to make her marathon debut, a little more than 26 years after she was born as her father, Olympian Steve Spence, was running the course. 

The third anniversary of the Boston Marathon bombings was marked on Friday (April 15) by remembrance of the dead and wounded.

Mayor Marty Walsh joined Governor Charlie Baker in laying wreaths on Boylston Street, the site of the first blast, where a moment of silence was held.

Deval Patrick, a former Governor of Massachusetts, addressed a gathering of more than 100 people in Copley Square.

"The silence we just observed, punctuated only by the distant tolling of that bell, spoke louder and more eloquently than anything I could possibly say here," he said.

"Sometimes we need just such silence."