Protesters against the summit could be seen along the barriers in the city, including some who were holding signs reading "No Nuke".

However, only the media was able to rival the number of security personnel on the streets on Sunday morning.

Around 3,700 reporters from around the globe have registered to attend the summit, while KBS, one of South Korea's leading television stations, has set up a glass-walled broadcast studio across from the venue's east gate.

Li Yi, a 25-year-old Chinese student at Dongguk University in Seoul, said he had noticed a growing number of police officers patrolling the city's subway stations during the last week.

"The station nearest to the hotel and the venue has been blocked to passengers, so if we want to get there we need to get off a stop earlier," he said.

Security has also been at the highest level at Gimpo and Incheon airports, both major transit hubs for delegates, since Friday.

Airport facilities have been temporarily drafted in from provincial areas in preparation for the increased traffic, and to prevent delays in arrivals and departures.

According to a report by The Korean Herald, roughly 40,000 police officers have also been deployed to increase safety nationwide.

The two-day Nuclear Security Summit will bring together 45 State leaders, including those of South Korea, the United States, China, Japan, Russia, India, Indonesia and France.