FBI investigating the 'mysterious deaths' of 11 Americans in the Dominican Republic this year have found that they all died of 'natural causes'.

As part of the investigation, the FBI carried out toxicology reports which 'were consistent with the findings presented by authorities' in the country.

Authorities in Dominican Republic have maintained that all 11 Americans died of natural causes. Autopsies reported by officials found that some of the victims died due to pneumonia, pulmonary edema, cardiac arrest or cerebral trauma.

In a statement, issued to FOX 43, the State Department's Bureau of Consular Affairs said: 'The results of the additional, extensive toxicology testing completed to date have been consistent with the findings of local authorities. Our condolences and sympathy go out to the families during this difficult time.'

The office of the Dominican Republic's Attorney General still has not offered a public statement since receiving the FBI's toxicology report September 16.

DailyMail.com has reached out to the FBI for further comment.

Khalid Adkins, who had been vacationing with his daughter in the Dominican Republic, was expected to fly back to the U.S. on June 23 but suffered kidney failure before takeoff and had to be rushed to a hospital, where he died June 26

Maryland couple Cynthia Day, 49, and Edward Holmes, 63 (both pictured left), had been staying in the Grand Bahia Principe La Romana hotel when they were found dead in their room by hotel staff on May 30. Jerry Curran (pictured right), 78, a former officer, died in January while staying at the Dreams Resort in Punta Cana

Guests staying at the Hard Rock's Punta Cana resort will no longer have access to a complimentary minibar refrigerator in their rooms

State Department data showed that 13 U.S. citizens died in 2018 while traveling to the Dominican Republic. At least 17 died in 2017.

The country is a longtime favorite vacation destination with tourists from the U.S, with 2.7 million visitors in 2017. But earlier this year, the Caribbean island came under scrutiny after several reports of the deaths of Americans while one vacation there.

Among the tourists that died was Jerry Curran, 78, who arrived with his wife at Dreams Resort in Punta Cana on January 22. He had dinner and drinks that night and spent the next couple of days in bed after falling ill. Curran died four days later after vomiting and becoming unresponsive.

Hard Rock Hotel and Casino in Punta Cana announced in July it eliminated all of its minibar dispensers from its guests rooms

Nathaniel Holmes, 63, and Cynthia Ann Day, 49, were set to head home, the day they were discovered dead at the Bahía Príncipe hotel in the Playa Nueva Romana resort May 30.

At least three Americans died during a seven-day span in June, including 56-year-old Vittorio Caruso, 56, who was declared dead June 17 after staying at the Boca Chica Resort in Santo Domingo.

Caruso was admitted to a local hospital due to breathing problems after consuming a beverage.

Khalid Adkins, 46, who had been vacationing with his daughter, was expected to fly back to the U.S. on June 23 but suffered kidney failure before takeoff and had to be rushed to a hospital, where he died on June 26.

Louisiana woman Susan Simoneaux, 59, died June 18 in New Orleans after being rushed to hospital with fluid on her lungs. Her death came a week after she returned to the U.S. after her honeymoon.

The deaths forced the Dominican Republic's Ministry of Tourism to adopt several measures that were introduced in September during a meeting with the U.S. Ambassador.

According to the improved safety methods, all hotel guest rooms must have emergency information and access to 911. A new multi-lingual emergency center for tourists will open in Punta Cana.

The tourism board is linking with Ecolab, an American based water, hygiene and energy technology lab to provide training and certification to inspectors in the Department of Tourism Services and Companies.

In July, the Hard Rock Hotel and Casino in Punta Cana announced it eliminated all of its minibar dispensers from its guests rooms.

The all-inclusive luxury hotel went forward with the removal of the small refrigerators that feature complimentary bottles of liquor amid backlash after the deaths of two guests at the Punta Cana resort over the last year.