"We created this rush, and we didn't have the ability to test or quarantine those people, and so that seeded the disease here," Gates told Fox News anchor Chris Wallace in an interview clip released on Friday.
"The ban probably accelerated that because of the way it was executed," Gates continued.
Sounding skeptical, Wallace pressed Gates to explain further, and the software billionaire continued, "March saw this incredible explosion, the West Coast coming from China, and the East Coast coming out of Europe."
"So even though we'd seen China, we'd seen Europe, that testing capacity and clear message of how to behave wasn't there," Gates noted.
In response to the international crisis, Trump banned travel to the US from China on January 31, and from continental Europe on March 11, adding the UK soon after.
The president has frequently pointed to the travel bans as evidence of his swift action in the face of the pandemic, saying that he imposed the China ban even as his advisors hesitated and his critics decried the move as racist and xenophobic.
Gates, a longtime philanthropist on issues of global healthcare and poverty, earlier this week issued a report saying the coronavirus pandemic has wiped out progress on lofty goals such as ending world poverty and hunger in the next decade.
The report outlines ways in which COVID-19 has wreaked economic damage and derailed progress on many of the global development goals adopted by the United Nations five years ago.
"The COVID-19 pandemic not only stopped progress, it kicked it backward," stated Gates, who co-founded Microsoft Corp, in a conference call with reporters. He and his wife Melinda set up the philanthropic foundation in 2000.
UN members unanimously passed 17 Sustainable Development Goals, known as SDGs, in 2015, that read like a blueprint of ambitious tasks from ending hunger and gender inequality to expanding access to education and health care.
The goals had a deadline of 2030.
"The SDGs represent the values that we have for humanity as a whole," Gates continued, adding, "The importance of the goals if anything is reinforced by the pandemic. After all, the pandemic has in almost every dimension made inequity worse."