Boston Marathon to take place amid tight security one year on from bombings

An additional 9,000 athletes will take part in the world's oldest marathon following last year's terrorist attack

Some 36,000 athletes were preparing to run the Boston Marathon on Monday, a year after the devastating terrorist attack that claimed three lives and left over 260 people injured at last year’s race.

Security has been stepped up as competitors, including Kenyan and Ethiopian runners who are consistently ranked among the world's fastest, line up for the 118th edition of the world’s oldest marathon.

“There'll be considerably more police presence,” Massachusetts Gov. Deval Patrick said on CBS' Face the Nation on Sunday.

“But we also don't want to have it, you know, kind of a race through a militarized zone. So it's about striking a balance, and I think we have struck that balance.”

Runners attending the event will be required to use clear plastic bags for their belongings and those planning to watch competitors as they cross the finish line will be encouraged to leave pushchairs and backpacks behind.

More than 100 cameras have been installed along the 26.2 mile route in Boston and around 50 “observation points” will be set up around the finish line “to monitor the crowd,” the Boston Athletic Association said.

Patrick said there have been no specific threats against the race or the city for the Massachusetts holiday of Patriots' Day.

“We're not taking that as a sign to sort of stand down,” he said.

“We're very prepared, and we're assuring people as much as we can that it'll be a fun day and a safe one."

Race organizers have allowed an extra 9,000 runners to take part this year to make room for the more than 5,000 athletes who were still on the course at the time of last year’s explosions, as well as for friends and relatives of the victims and for those who made the case that they were "profoundly impacted" by the attack.

Lelisa Desisa of Ethiopia and Kenya's Rita Jeptoo, who crossed the finish line on Boylston Street about three hours before the pressure cookers went off, will return to defend their titles. Desisa returned to Boston last autumn to donate his first-place medal to the city as a gesture of support.

Jeptoo, who also won the race in 2006, said she is hoping for a third victory - and one she can enjoy.

“It was very difficult to be happy. People were injured and children died,” she said of last year's marathon.

“If I'm going to win again, I hope I can be happier and to show people, like I was supposed to last year.”

No American athlete has stood atop the podium on Boston's Boylston Street, not far from the site of last year's bombing, since 1985 when Lisa Larsen-Weidenbach of Michigan won the women's race. The drought has been longer for US men - Greg Meyer of Massachusetts won in 1983.

But there are several US hopefuls in the field, including Ryan Hall of California, who placed third in 2009 and Desiree Linden, who missed winning by just two seconds in 2011.

Chechen Dzhokhar Tsarnaev and his brother Tamerlan, who died following a shootout with police in the early hours of 19 April, 2013, are alleged have detonated the two bombs at around 2.49pm at the Boston Marathon on 15 April last year.

Dzhokhar, 20, is awaiting trial on 30 federal charges.

Additional reporting by agencies