Kenya's two-time Boston Marathon champion Moses Tanui and former world marathon record holder Paul Tergat are among elite Kenyan runners who have expressed outrage at the Monday bombing attack on the event that left three dead and scores injured.

Speaking from Eldoret on Tuesday, Tanui who won the 1996 and 1998 men's titles at Boston termed the bombing incident 'unfortunate' while expressing relief that the nine Kenyan runners who competed at the event escaped unharmed.

"We have to call the event that happened unfortunate. Athletics is one of the sports that unites the world but some people with evil minds want to ruin the sport

"We are lucky our athletes were not hurt. Boston is one of the top marathons in the world and I hope next year they will tighten security so that the race can continue," Tanui, now a keen golfer, stated.

"If you are in that position one will be scared but the good thing for us is that the elite athletes had already crossed the finish line but it is a big blow to the country (America) since most of those affected were fun runners and others competing for charity which is sad," the 1991 world champion over 10,000m added.

Tergat, who won the 2005 New York race, told of his anguish as he witnessed the events unfold on television.

"All of us are really sad that some members of the society can bring something like this in the sport and affect people who are harmless and having fun.

"I hope this is not going to send the wrong signals but as a sportsman it was so painful to watch since sports is meant to unite people. We don't need this at these events since they bring people from all walks of life together, men, women and children," he explained.

Tergat, who is now a UN goodwill ambassador among other diplomatic roles added his concern that the Boston bombings could deprive his compatriots who have excelled in distance running livelihood.

"It's too early to say what the impact of these attacks will have on the sport but the fear is without the many people who turn up, we will not have sponsors coming to these events and it could affect the income.

"Our children earn and youth earn a living we converge together in thousands for fun, fitness and health and what was unfolding it touched me, when I saw it last night, I could not believe."

He urged those who will compete in Sunday's London Marathon to take heart and not to allow the atrocities to dampen their resolve.

"For other runners going to London, they should not fear, because I want to believe it was one off thing and will not occur anywhere else."

Monday's attacks at the finish area of Boston Marathon raised concerns about the psychological state of Kenyan elite runners who will feature in Sunday's London Marathon.

Among them is world marathon record holder Patrick Makau, who was scheduled to arrive in London on Tuesday morning.

"Patrick has his first appearance scheduled for Wednesday at the Virgin London Marathon Stage.

"All of us at the IAC, clients and management team, are still in a state of disbelief and it will take some time for these developments to sink in and for all of us to reflect.

"As this tragic news broke, all our friends and all people present and affected were in our thoughts and prayers and we followed and we are to continue to follow developments," Makau's manager Zane Branson said in a statement.

"Shocking events in Boston are, probably and to a certain extent, going to change marathons, half marathons and road races, but it is our firm belief that good, camaraderie and resilience of runners of all abilities are going to prevail," he added.

Defending champion and Olympics bronze medallist Wilson Kipsang, two-time world titleholder Abel Kirui, 2011 Boston crown holder Geoffrey Mutai as well as former London winners, Emmanuel Mutai and Martin Lel are other star Kenyan runners in the men's roster.

Olympics silver winner Priscah Jeptoo and 2011 Berlin winner Florence Kiplagat are in the corresponding women's field of the event whose security arrangements have been reviewed following the gruesome events in Boston.

Tanui, however, believes the bombings will not have an adverse impact on the earnings of Kenyan athletes who have turned to such events to make a living.

"Marathons like Boston are organisations and as such, income cannot be affected but the biggest concern is people who come to witness these races could be afraid to come out and enjoy the sport," he explained.

"We are grateful and relieved that all our runners are safe. The incident was very sad and disturbing and our prayers go out to the Boston community and all those involved. It is sad that sporting events can be targeted like this," Athletics Kenya chairman boss Isaiah Kiplagat said in his reaction to Monday events.

Meanwhile, Kenyan athletics officials have also condemned the terrorist act that saw two blasts rock Boston Marathon on Monday.

Athletics Kenya (AK) Secretary General David Okeyo said the cowardly act must not dissuade athletes focus ahead of their intended race at the London Marathon on Sunday.

"What happened in Boston remains just a lone incident that must not be allowed to repeat or discourage other athletes from running. I want to urge Kenyans athletes who were preparing to compete at the London Marathon to go ahead and run bravely because their security will be guaranteed," said Okeyo Tuesday in Nairobi.

"This is a silly act. Of course the sole responsibility of security for any event lies with the organizers, but this shows the extend that the countries security system need to take whenever events of such magnitude happen. You never know where it might happen," he said.

Okeyo said marathon is run on road over vast distance and sealing it off completely is a challenge.

"This can also happen inside stadiums and it is a call for us in the sports world to tighten our nuts on the security in coordination with national governments," said Okeyo.

In January, Kenyan runner Edwin Kipsang Rotich was tackled by a member of the public when leading at the Kings Race marathon in the Brazilian city of Cuiaba - but he still managed to go on and win.

"These terrorists have no shame. Sports unite people, we know nothing about racism, segregation or any evil, ours is a career that brings all people together and to be the target of such cowardly attacks is absurd," said Okeyo.

Kenya's Rita Jeptoo and Ethiopia's Lelisa Desisa won the women's and men's Boston Marathon, continuing African runners' dominance in the sport.

Another Kenyan woman Sharon Cherop, winner in 2012, was third. In the men side, Micah Kogo made his debut and was able to clinch silver. Wesley Korir, winner in 2012, was fifth while Dickson Chumba settled for seventh spot.

Kenyan embassy in Washington confirmed that no Kenyan was involved in the incidence and all are safe.

This comes as Athletics Kenya meets in Nairobi to select its provisional squad for the World Championships in Moscow, Russia in August.

AK Chairman Isaiah Kiplagat said, the results in London and Boston will not be considered as they look at consistence and year-long results in naming the final team.