Security on Sentosa Island has increased. The designation means restrictions and new rules are in effect, Singapore's Straits Times reported Tuesday.
Those measures include new security measures, "spot checks," including bag and body checks, according to the report.
Police can ask for identification and banned items include drones, flags, banners and flammable materials.
Locals are also prohibited from driving certain makes and models of cars, including the black 7-series BMW. The rule remains in effect from June 3 to 30, weeks after the summit concludes.
The ordinance may be taking a toll on businesses on the island, including Universal Studios Singapore, Marine Life Park and area hotels.
The island is accessible only by a 700-meter bridge and cable cars -- making it an ideal location for the summit.
White House Press Secretary Sarah Sanders confirmed Tuesday at the island's Capella Hotel would host the summit. The U.S. delegation stayed there during working-level talks.
On Monday, the hotel was blocked from public access and was not taking reservations for June 12, according to South Korean news agency Yonhap.
The hotel was the site of breakthrough talks in 2015 between the leaders of China and Taiwan.
The White House disclosed Monday the summit is to take place at 9 a.m.
NHK reported top U.S. and Japanese diplomats would meet in Seoul for a debriefing, following the meeting.