HAVANA, CUBA (REUTERS) - The sunny outlook from tourism in Cuba based on the sharp rise in US visitors in recent years could soon come crashing down.

This, after the US State Department warned on Friday against travel to Cuba, after a spate of mysterious attacks on US embassy personnel.

At a Havana conference organised by the Responsible and Ethical Cuba Travel (RESPECT) association, coordinator Bob Guild said, despite the warning, Cuba remains a safe destination.

Respect coordinator Bob Guild says: "There is no place safer for Americans to come than Cuba in the entire world, and that's been the case. No incidents against anyone other than the 21 diplomats. So, our conclusion was that it very likely seems to be political statement, not a warning from people that are worried about their health."

The warning was the second notice from the Trump administration.

The president in June ordered tighter restrictions on travel to Cuba, which had previously been opened in the wake of the 2014 US-Cuban detente under former US President Barack Obama.

Holbrook Travel founder Andrea Holbrook says businesses like hers could suffer if fewer Americans visit.

Holbrook says: "Cuba is an important destination for us volume-wise so we are concerned about the impact that this is going to have on our 2018 and 2019 business."

For Cubans, like vendor Jorge Capote, who benefit from the US$300 million (S$407 million) in revenue from US tourism, it is simply the cost of doing business with a former foe.

Says Capote: "If they (US tourists) don't come, it's because the president (Trump) determined that they shouldn't come. Don't come then. We'll continue to sell. With the (US) embargo, with Americans or without Americans, either way I've lived to my old age, fifty something years old".

With or without American tourists in Cuba, it is a reality that many there are prepared to face.