Story highlights The list of banned items is part of revamped security following last year's deadly bombings

The Boston Marathon will be held on April 21

Organizers are preparing for 36,000 entrants this year.

As part of revamped security following last year's deadly bombings, the Boston Marathon has banned various items for the 2014 race, including bags and strollers.

The bombs placed in backpacks exploded near the finish line last year, killing three people.

Backpacks, handbags, suitcases and similar items are prohibited from entering any marathon venues this year.

So are containers with more than 1 liter of liquid, costumes covering the face, and bulky clothes such as vests with pockets.

Photos: The arrest of Dzhokhar Tsarnaev Photos: The arrest of Dzhokhar Tsarnaev The backlash over Rolling Stone's cover photo of Boston Marathon bombing suspect Dzhokhar Tsarnaev led to the release of new photos of his capture. The images, released by Police Sgt. Sean Murphy on July 18, 2013, show Tsarnaev as he emerges from the boat where he hid in Watertown, Massachusetts. Hide Caption 1 of 5 Photos: The arrest of Dzhokhar Tsarnaev Tsarnaev was found in a motorboat dry-docked in the backyard of a Watertown home on April 19, 2013. Hide Caption 2 of 5 Photos: The arrest of Dzhokhar Tsarnaev "This guy is evil," Murphy said. "This is the real Boston bomber. Not someone fluffed and buffed for the cover of Rolling Stone magazine." Tsarnaev has pleaded not guilty to 30 federal charges related to the marathon bombings. Hide Caption 3 of 5 Photos: The arrest of Dzhokhar Tsarnaev Tsarnaev exits the boat during his capture. The pictures were taken by Murphy and published online by Boston Magazine. Hide Caption 4 of 5 Photos: The arrest of Dzhokhar Tsarnaev Police tend to Tsarnaev after his detainment. Hide Caption 5 of 5

Marathoners will be allowed to carry clear, plastic bags provided by the organizers. They can also run with small fanny packs for medication and cell phones, and fuel belts that hold a bottle under one liter.

Large flags or signs bigger than 11 inches x 17 inches are also banned from marathon venues. Marathon venues include the start and finish areas, the course, athletes' village and areas where official events are held.

Unregistered runners and cyclists, who jump into the race along various points, are not welcome this year, either.

"We are aware that many people want to participate in some way in this year's Boston Marathon as a display of support," the statement said. "But we ask that those who are not official participants to refrain from entering the course for the safety of the runners and themselves."

On April 15 last year, double bombings hit the Boston Marathon , which attracts elite runners from all over the world. They exploded within 12 seconds of each other. Three people died and 264 others were injured.

Two brothers, Tamerlan and Dzhokhar Tsarnaev, are suspected of planting the homemade bombs near the finish line.

The latter faces a potential death penalty and appears in court in November. His brother was killed in a police shootout shortly after the bombings.

The 118th Boston Marathon will be held on April 21.