The US possession of Puerto Rico will require all visitors arriving by air to present a negative COVID-19 test or be held under quarantine at their own expense, officials said Tuesday.

Starting on July 15, all visitors -- including those arriving from other parts of the United States -- must show airport authorities the results of a molecular test, with samples taken from a nostril.

The test must be no more than 72 hours old, a statement from island authorities said.

If arrivals have not taken a test, one will be administered immediatly and the passenger must remain quarantined until results are available.

If the results are positive, the visitor must be held in quarantine for 14 days and obligated to pay for all expenses, including medical.

Governor Wanda Vazquez said she understood that the strict measures and social distancing from loved ones were "difficult" but said "necessary precautions must be taken to avoid infecting others."

Puerto Rico, population 3.1 million, has registered more than 7,200 novel coronavirus cases and 153 deaths.

On March 15 island authorities were the first in the US to order a lockdown in an attempt to halt the spread of the disease.