Two British female tourists were sexually assaulted and robbed on the Caribbean island of Tobago, officials said.

Local newspaper reports said a knife-wielding man broke into the Black Rock Dreams guesthouse where two couples were staying.

The property co-ordinator of the apartments, who did not want to be named, told the Trinidad and Tobago Express that the intruder was masked and carrying a 10-inch knife but acted "in a very professional manner". He said the incident lasted between 45 minutes and an hour.

Trinidad's British High Commission spokesman James Dolan said officials were working with police but declined to provide more details.

The Foreign Office is urging travellers to be cautious and to stay in hotels with tight security measures.

The assault came less than two weeks after a Swedish couple were killed in an apparent robbery on the island.