The tournament, scheduled to be held in Washington in the United States from August 13, was set to mark the resumption of the men's professional tennis circuit in March after it was shut down in March because of the spread of the virus.

The ATP said the decision to cancel the tournament was made because of "continued uncertainties affecting the ability to meet key planning deadlines."

"It’s disappointing that due to these unprecedented times, the Citi Open will not be able to go ahead this year," said Andrea Gaudenzi, ATP chairman.

"I know how hard Mark Ein and his team have worked to adapt to new and continually changing conditions and would like to recognise their outstanding commitment to staging the event. 

"Unfortunately for the moment there are still large factors at play which are outside of our control.

"We look forward to the Citi Open returning as one of our signature American events in 2021."

The tournament's chairman Mark Ein called the decision to cancel this year's event "heartbreaking."

"With only 23 days left until the start of the tournament, there are too many unresolved external issues, including various international travel restrictions as well as troubling health and safety trends, that have forced us to make this decision now in fairness to our players, suppliers and partners, so that they can have certainty around their planning," said Ein.

The ATP are continuing to work closely with the United States Tennis Association (USTA) on plans to stage the Western & Southern Open and US Open, scheduled to take place back-to-back in New York from August 20.

The ATP is continuing work on a revised 2020 calendar with a further update on a provisional schedule of events for the remainder of the season expected in the next fortnight.

The Women's Tennis Association (WTA) Tour is set to resume on August 3 with a tournament in Palermo in Italy.