The apology came after criticism from his political opponent Cal Cunningham.
Tillis, a North Carolina Senator seeking reelection in 2020, tweeted a photo Thursday night showing him wearing a mask on the South Lawn of the White House.
I am honored to be in Washington for President @realDonaldTrump's acceptance speech for the @GOP nomination, where he will share with America our continued vision of freedom, prosperity, and opportunity to live the American Dream. #RNC2020 pic.twitter.com/7wUptHJrL3— Thom Tillis (@ThomTillis) August 28, 2020
But other images later surfaced on social media showing Tillis not wearing a mask, seated next to other attendees who were also not masked.
Tillis has previously said that every elected official should wear a mask.
In an interview in April, he said: "The last thing I want to do is see an elected official who is responsible for imposing a stay at home order or a wear a facial mask order out in public and not with a mask on."
His Democratic opponent, Cunningham, criticized Tillis for his double standard on Twitter saying, "Sen. Thom Tillis criticized folks for not wearing masks, until Washington Republicans were the culprits. His attendance last night shows North Carolinians that the rules don't apply to his colleagues in Washington-and that his talk about fighting this pandemic is just that: talk."
Sen. Thom Tillis criticized folks for not wearing masks, until Washington Republicans were the culprits. His attendance last night shows North Carolinians that the rules don’t apply to his colleagues in Washington—and that his talk about fighting this pandemic is just that: talk. https://t.co/ctM2xLzrYn— Cal Cunningham (@CalforNC) August 28, 2020
Tillis issued this apology shortly after, while still taking a political jab at Cunningham:
"I've stressed the importance of mask wearing throughout this pandemic and have tried to lead by example on this issue, but last night I fell short of my own standard. The difference between Cal Cunningham and I is that I can accept responsibility for my actions, while he lies and makes excuses for his, like how he has misused taxpayer dollars for his own personal gain and broke his promise not to raise taxes on hardworking North Carolinians."
Mecklenburg health officials announced Friday morning that four people associated with the RNC in Charlotte tested positive for COVID-19.