The United States has warned travelers not to visit Cuba and ordered 60 percent of U.S. diplomats to withdraw, in a dramatic response to a string of mysterious sonic attacks on U.S. diplomats in Cuba.

The move to the already delicate relationship between the two cold war adversary caused major blow, after the ancient relationship under President Barack Obama (Barack Obama) presidency began to thaw, start a slow process of reconciliation, but in Donald Trump (Donald Trump) is in the White House has be part of the reverse.

"In the Cuban government to ensure the safety of Chinese diplomat in Cuba before the embassy in China will shrink to only by emergency personnel stationed, as far as possible to reduce the number of students who are exposed to the risk of diplomats," U.S. secretary of state, Rex Tillerson, Rex Tillerson said.

The Cuban government has denied any role in the incidents and is investigating, but says it has so far failed to identify any causes.

The incidents have caused dizziness, partial deafness and nausea among 21 U.S. diplomats and their families.

Several diplomats in Canada were also affected.

Mr. Tillerson said there were no reports of the impact on ordinary U.S. citizens, but noted that some of the sound attacks occurred in hotels frequented by americans.

He added that the state department "does not have a definitive answer to the cause or source of such attacks, nor does it suggest a means to reduce risk".

Tourism is very important to the economy, the country's economy has been Hurricane "Alma," the damage caused by Hurricane (Irma) and the closest ally, the socialist venezuela cut subsidised oil supply.

About four million tourists visited Cuba last year, including more than 600,000 cuban-americans and American tourists.

The evacuation of U.S. embassy personnel also means the U.S. will suspend visa applications for cubans seeking to travel to the United States in Havana.

U.S. officials declined to confirm speculation that the attacks were initiated using a device that emits sound waves, which have the ability to harm humans.

The us government has used "event" to describe the situation, and has now switched to the word "attack".

But U.S. officials declined to say whether the government believed the Cuban government had played any role during the months of acoustic attacks.

During a meeting in Washington this week, he reminded the Cuban foreign minister Bruno Rodriguez (Bruno Rodriguez) : according to the Vienna convention, the country has the obligation to protect diplomats and their families.

Rodriguez said after the meeting that Cuba had "impeccable records" in complying with the Vienna convention and urged the United States not to draw "hasty conclusions" based on uncertain evidence.

Unusually, Cuba has invited the federal bureau of investigation and the royal Canadian mounted police (RCMP) to assist in the investigation.