"So I said to my people, 'Slow the testing down please.' They test and they test".
He complained that robust coronavirus testing was making his record look bad - and suggested the testing effort should slow down.
Trump's comments came as states have seen a resurgance in COVID-19 cases after opening up.
Demonstrators march outside the BOK Center where President Trump will hold a campaign rally in Tulsa, Oklahoma Saturday, June 20, 2020. Blame phantom protesters - as the Trump campaign did in a statement - for blocking access to the rally site.
Brad Parscale, Mr Trump's re-election campaign manager, who initially boasted of the huge turnout anticipated at the event, tweeting that it would be the "biggest data haul and rally signup of all time by 10x", said on Saturday night that "radical protesters" had interfered with attendance.
"The unhinged left-wing mob is trying to vandalize our history, desecrate our monuments, our lovely monuments", Trump said.
The narrative of a trouble-free campaign event was punctured, however, when the campaign announced just hours before the rally that six members of its Tulsa advance team tested positive for coronavirus.
He is returning to the campaign trail after a cascade of setbacks in recent weeks, including Supreme Court decisions overturning his administration's policies and the pending release of a searing book by John Bolton, his former national security advisor.
Trump, 74, explained that he was hot and exhausted after saluting "600 cadets", adding he found himself in a precarious situation due to the fact that he was wearing leather-bottomed shoes and it was a long and steep ramp leading off the stage. Mr Trump, who spoke for nearly two hours on a range of topics, referred to those in the stadium as "warriors", while blaming the media and protesters for keeping supporters away.
Instead, his weekend rally in Oklahoma highlighted growing vulnerabilities and crystallized a divisive reelection message that largely ignores broad swaths of voters - independents, suburban women and people of color - who could play a crucial role in choosing Trump or Democratic challenger Joe Biden.
Trump campaign officials said protesters prevented the president's supporters from entering the stadium. The technological savvy of their generation has turned political: they knew that the Trump campaign harvests information from ticket reservations, bombarding applicants with texts and requests for donations.
But areas outside the arena appeared to be sparsely populated about an hour before the president's arrival.
Trump proceeded to show the crowd at his rally that he was capable of drinking from a glass of water, before throwing the glass to the ground as the crowd cheered.
Inside the barriers, the campaign was handing out masks and said hand sanitiser also would be distributed and that participants would undergo a temperature check.
"Without question, it has more names than any disease in history", said President Trump, "I can name "kung flu". "I haven't caught a cold or a flu in probably 15 years, and if I haven't caught a cold or flu yet, I don't think I'm gonna catch COVID".
EA Play Live 2020 live-stream and blog
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