The advisory sent out by the International Maritime Bureau (IMB) on Wednesday has reportedly led to increased maritime and air patrols but has not affected shipping traffic. Singapore's Navy has put more ships into the strait and boosted the Coast Guard presence to prevent an attack on the island itself. Police boats have been “tasked to look out for, and inspect, small boats that come close to large vessels that are berthed at anchorages here,” reports Singapore’s Straits Times.
Malaysia’s Coast Guard said it has increased security in the narrow waterway, and Indonesian Defense Minister Purnomo Yusgiantoro told Reuters the country has also stepped up patrols. “Oil tankers can pass, but we will increase our readiness," the minister said.
The original tip-off came from Japan, Reuters quoted a Thai official as saying, which informed the IMB that ships could be hijacked. A bureau official reconfirmed that this was a terror threat, not a piracy threat. (Read about Japan’s increased efforts against piracy here.)