A second terrorist attack in as many days in the southern Russian city of Volgograd has raised fears that Islamist militants are coordinating bombings as the country prepares to host the 2014 Winter Olympic Games in Sochi.

Monday’s attack claimed 14 lives and injured dozens more after an explosive device planted on a trolleybus detonated during rush hour near the city center, officials said.

The explosion came less than 24 hours after a blast at the entrance of the city’s central railway station killed 17 and critically injuring more than 40 on December 29 in what authorities said was a suicide bombing. 

The most recent attack occurred in a trolleybus full of passengers traveling from a suburb area of Volgograd to the city center. The explosion completely destroyed the trolleybus and blew out windows of neighboring houses.

Local authorities reported 14 people dead but authorities said that number could increase. The Ministry of Health reported 28 people wounded. A six-month old infant was in critical condition, according to his doctors.

According to preliminary data, the attack was not committed by suicide bomber. The explosive device was placed in the middle of the cabin and activated remotely.

"I left the house and heard a loud bang and people screaming. I did not realize at first that it was trolleybus. It was so damaged, completely blown apart," a local resident told RIA Novosti.

Local authorities said the explosives used in the December 29 blast at the railway station had the strength of what was equivalent to 10 kilograms of TNT. It killed 17 people, injured more than 40.

“The explosion was so strong that it shook our building,” an employee of a shop located in front of the station said. “We rushed out to the street and saw the main entrance with people spread on the stairs. The explosion blew out all the windows in the building, and black smoke was pouring from the windows of the first floor."

Conflicting reports first said the explosion was committed by a suicide bomber, with some reports saying it was a female. Later, the Investigation Committee reported that the attack might have been committed by a man.

Volgograd is located in the south of Russia almost 700 kilometers, or 435 miles, from the site of the Sochi Olympic Games. The Games are scheduled to begin in early February.

Monday’s explosion was the third terrorist attack in two months. On October 21 a suicide bomber blew up a passenger bus, killing seven and injuring 37. The series of attacks has raised fears that Islamist militants from Russia’s restive North Caucasus region may be planning more ahead of the Games.

However, the president of the Russian Union of Security Enterprises, Sergey Goncharov, said in an interview with RBTH that the attacks in Volgograd likely occurred as local officials focused on the struggle for power rather than anti-terrorist measures in the region.

“After the first explosion on the bus, security forces found and destroyed all of the organizers, so new attacks look more like a revenge and an attempt to prove that the militants are still able to strike," Goncharov said.

Goncharov, who is also the president of the Association of Veterans of Alpha group, Russia’s elite counterterrorism unit, added that it is unlikely that the latest terrorist attacks are connected with the Olympics, since there is more than a month before the Games will begin.

Dmitry Babich, a political columnist with the Voice of Russia, agreed and said that the attacks were more likely connected to the New Year holidays.

“For the Islamists, it is the most obnoxious holiday,” he said. “There are two reasons: they consider it a pagan holiday , and it brings together people from all the former Soviet Union, including the Muslims.”

Babich said he believed the Volgograd attacks will have no impact on the political situation in the country.

“Because of the nature of our politics and society, such attacks are not as important as they would have been in the West. You can kill 100 or 200 people in Moscow, but no change in policy towards the North Caucasus or the terrorists will happen,” he said. “[Russian President Vladimir] Putin does not change this policy even under the influence of the deadliest terrorist attacks. This policy is similar to Israeli."

Babich added that Sochi’s security will now be intensified, and any attempt of an attack “would be too costly for the Islamists.”