Injured people are assisted after an incident on Westminster Bridge in London, March 22, 2017. Reuters

An attack outside of Parliament in London Wednesday was being treated as an act of terror by local officials, as the government building was put on lockdown and Prime Minister Theresa May was evacuated from the area following an apparent spree of violence including a stabbing. Several reports indicated dozens of victims were involved in the incident, which may have included using a vehicle to drive into large crowds, before the suspected attacker was shot by police officers just steps away from the highest legislature in the U.K.

Dal Babu, former chief superintendent of London’s metropolitan police department, said in an interview with CNN that London was still considered "one of the safest cities in the world" despite Wednesday’s attack, as questions emerged surrounding citywide terrorism security measures.

Read: London Parliament Attack Live Updates: Gunshots, Injuries Reported In Westminster

Meanwhile, it remained immediately unclear if the attack outside of Parliament was connected to several bodies found across London, including multiple images of people who were photographed on Westminster Bridge and shared across social media Wednesday. Eyewitnesses then said a man carrying a knife chased down countless tourists and residents photographing the Big Ben monument before engaging with local law enforcement.

Injured people are assisted after an incident on Westminster Bridge in London March 22, 2017. Reuters

"We were taking photos of Big Ben and we saw all the people running towards us, and then there was an Asian guy in about his 40s carrying a knife about seven or eight inches long," witness Jayne Wilkinson told the Independent Wednesday. "And then there were three shots fired, and then we crossed the road and looked over. The man was on the floor with blood."

No global terror group had immediately took responsibility for Wednesday's attack, though New York Times reporter Rukmini Callimachi wrote on Twitter digital messaging platforms used by the Islamic State, otherwise known as ISIS, were flooded with chatter surrounding the incident in London. The reporter shared several screenshots showing apparent ISIS fighters celebrating the Parliament attack.

Reports of a bus being used in the suspected terror attack on London echoed similar incidents throughout Europe, including last year's attack on France's Bastille Day festivities, when terrorists drove through crowds of party-goers in Nice, France.

London, along with the rest of the U.K., has seen heightened security measures following global terror acts targeting holiday celebrations and other public gatherings. The U.K. also has more closed-circuit television (CCTV) coverage than most advanced nations, with nearly 5.9 million cameras now keeping a close watch over city streets and popular locations.

The threat of attacks organized by the Islamic State against London prompted heightened security and surveillance during the 2017 New Year celebrations across the city, with 3,000 police officers protecting London on New Year’s Eve.

Wednesday marked the one-year anniversary of the coordinated terrorist attacks in Brussels, Belgium, targeting an airport in Zaventem and the Maalbeek metro station in central Brussels. The U.K.’s international terror threat level was listed as "severe" during Wednesday’s attack.