The Foreign Office spokesman said: "We cannot comment further on the nature of the threat at this time."
More top news
Severe flooding has forced more than 1,000 people from their homes in southeast Texas, and at least eight people have died across the state.
Facebook, Twitter, YouTube and Microsoft have agreed to block illegal hate speech from their European services in less than 24 hours.
The 29-year-old is in a Perth hospital following the incident off a beach in Mandurah in Western Australia.