This year's Carnival will be held Monday and Tuesday. The US Embassy in Port of Spain, capital of the two-island Caribbean nation, issued a security alert Thursday night, saying a plot had been thwarted but advising US government personnel "to exercise additional caution and increased situational awareness if they participate in Carnival events."The United Kingdom also issued a "Foreign Travel Advice" for the West Indies country on Thursday. "Terrorists are very likely to try to carry out attacks in Trinidad and Tobago. Attacks could be indiscriminate, including in crowded spaces and places visited by foreigners," the advisory said, adding authorities in that country have made arrests. The US military and intelligence have long considered Trinidad and Tobago a home to ISIS sympathizers. Individuals who have left Trinidad and Tobago have been involved in terrorist acts and committed killings in Syria, Adm. Kurt Tidd, head of US Southern Command, said in April 2017.In a news conference Thursday, a Trinidad and Tobago police official, Michael Jackman, said the disruptions were in the form of "criminal activities." He did not elaborate on whether the threat was terror-related. Police uncovered a threat to disrupt the Carnival activities and detained "several persons of interest," Jackman said in video provided by CNN affiliate CNC3 Television. The nation's police and defense forces are working together to ensure a safe and secure environment for the Carnival, he said."The public, as usual, should remain vigilant," he added.