USTA says it is assessing all options but is not now implementing any changes to its schedule.
The US Open, the final Grand Slam on the calendar, is scheduled to run August 24-September 13 at the Billie Jean King Tennis Centre in Flushing Meadows, New York.
The French Open has also come under attack from the US Open and many players for their sudden decision, and is being accused of acting selfishly and independently when tennis should be working together.
The start was pushed back to September 20, a week after the scheduled conclusion of the U.S. Open, making it the fourth Grand Slam of the year.
Bernard Giudicelli, FFT president, said: "We have made a hard yet courageous decision in this unprecedented situation, which has evolved greatly since last weekend".
"Although no one is ready to predict what the state of affairs can be on 18th Might, the present confinement measures have made it inconceivable for us to proceed with our preparations and, consequently, we're unable to maintain the event on the dates initially deliberate".
Previously cancelled tournament in Indian wells, the final of the Federation Cup, and for six weeks suspended the conduct of all tournaments of the Association of tennis professionals (ATP) and Women tennis Association (WTA).
"This is a tournament many African football lovers look forward to but the severity of the current health crisis makes it tough for us to host now".
The coronavirus pandemic has caused widespread corruption to the worldwide tennis calendar with many events either cancelled or postponed leaving tennis players, coaches and tournament employees either severely out of pocket or unable to earn a living at all.
French President Emmanuel Macron announced Monday that for at least 15 days, people in that country would only be allowed to leave their homes for necessary activities such as shopping for food or going to work.
The organizers have confirmed that all tickets already purchased can be refunded or exchanged to accommodate the new dates.
The ATP and WTA are yet to give a public response but many players reacted with surprise, bemusement and anger, particularly at the lack of consultation on such a major scheduling decision.