"Some tests came back inconclusive on other viruses, which is common", de Blasio spokesman Eric Phillips said on Twitter, adding that the tests were being re-administered.
Dozens of vehicles surrounded the aircraft at JFK airport, with local media reporting that people were coughing and had high temperatures.
The CDC said in its statement that as many as 100 passengers and crew members reported feeling sick during the flight from Dubai.
There were approximately 521 passengers on the flight.
Pictures posted on social media showed ambulances lined up on the tarmac next to the A380, the largest passenger airliner in the world. The airline later confirmed that three passengers and seven crew were transferred to hospital for "further medical care and evaluation".
Shortly before 10:30 a.m., Emirates Airlines said in a statement via its official Twitter account that only 10 passengers from Dubai had fallen ill.
Ten people were hospitalized after an global flight landed at JFK Airport on September 5, 2018.
The Centers for Disease Control and Prevention says none of the 12 passengers coming to Philadelphia on American Airlines flights from Paris and Munich exhibited fevers. The Centers for Disease Control, however, said that of the 549 people on board 11 people had been taken to the hospital.