On Monday, the wealthy city-state had declared a central region that is home to its foreign ministry, the U.S. embassy and several hotels, as a special zone from June 10 to 14.
In its online gazette, the government said the amended zone included Sentosa and an area of the sea stretching more than 1 km (0.6 mile) off its southwestern shore.
A smaller area in the centre of the island that includes the Capella hotel, which media have mentioned as a possible venue for Tuesday's talks, will see a greater police presence.
There has been no confirmation of the venue for the summit to discuss ending the North's nuclear weapons programme in return for diplomatic and economic incentives, although several Singapore hotels have figured as candidates.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
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