Britain on Sunday asked its citizens in Tunisia to be on alert, warning that further terrorist attacks in the country are possible after the beach resort massacre by an IS militant that left 38 people dead, including 15 Britons.

In an updated travel advice, the Foreign Office said, “Further terrorist attacks in Tunisia, including in tourist resorts, are possible, including by individuals who are unknown to the authorities and whose actions are inspired by terrorist groups via social media.”

Asking those who remained in Tunisia to be vigilant, it said, “You should be especially vigilant at this time and follow the advice of Tunisian security authorities and your tour operator.”

At least 38 people were killed after an Islamic State militant opened fire on a beach in front of hotels in the Tunisian resort of Sousse on Friday. The victims include 15 Britons, though officials have warned that the toll is expected to rise.

Another 39 people were injured, including 25 Britons, in the attack.

Meanwhile, UK Home Secretary Theresa May, who chaired a meeting of the UK Government’s emergency Cobra committee today, said that she has seen no evidence so far that the beach resort was targeted specifically because it is popular with British tourists, the BBC reported.

She, however, warned, that the risk to Britain had become “more diverse” in recent years — including not just the risk of groups plotting over time to strike in the country but also that of spontaneous attacks by a “lone wolf“.

She said that some 40 plots had been foiled in the UK in the past decade.

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