"We think it is unlikely that we would be to the point at the end of August to be able to have a jam packed 19,000-person convention in the Spectrum arena", Cooper said.
Trump blasted Cooper as "still in Shelter-in-Place Mode" on Twitter late Tuesday night, and said the decision was forcing Republicans "to seek another State to host the 2020 Republican National Convention".
Cooper had sent a letter to the Republican Party earlier in the day explaining that the convention would have to take place on a smaller scale with social distancing measures and mask-wearing due to recommendations from health authorities to stop the spread of the coronavirus.
A traditional Republican convention brings together roughly 2,500 delegates, the same number of alternate delegates and many times more guests, journalists and security personnel.
McDaniel responded, tweeting that the GOP still wants to hold the convention in Charlotte but that "we have an obligation to our delegates and nominee to begin visiting the multiple cities and states who have reached out in recent days" about hosting a relocated RNC.
In a letter to Cooper last week, McDaniel asked him to approve a series of safety protocols and logistical measures that Republicans agreed to, including health questionnaires and thermal scans for fever.
"The people of North Carolina do not know what the status of COVID-19 will be in August, so planning for a scaled down convention with fewer people, social distancing and face coverings is a necessity", Cooper wrote.
Demands for a full-scale convention had raised alarms in North Carolina, which is facing an upward trend in its virus cases.
Republicans in Georgia, Texas, and Florida have offered to host the convention.
Tennessee Gov. Bill Lee said that GOP officials are coming to scout Nashville on Thursday, calling the city 'the best place in America to have a convention. Las Vegas, which was the runner-up before Charlotte was chosen, is also reportedly in the mix, as are Orlando and Jacksonville.
Democrats are deciding whether to hold their August 17-20, originally planned for Milwaukee, virtually amid fears a massive gathering could lead to a new wave of COVID-19 cases.