RALEIGH, N.C. (AP) — North Carolina Republican Sen. Thom Tillis and Democrat Cal Cunningham traded accusations on the government's COVID-19 response in a debate Monday, kicking up a notch a campaign that could determine which party controls the Senate.

Tillis, who is seeking a second term, was largely the aggressor in their first debate for the seat in a closely divided state and a closely watched race. Democrats need to win four additional seats in November to ensure control.

Tillis, a former House speaker who beat incumbent Kay Hagan six years ago, said he's worked hard while in Washington to get relief funds to North Carolina's schools and for vaccine research. He said President Donald Trump also took a “good first step” early on by imposing a travel ban from China.

Tillis accused Cunningham of failing to back the Senate’s latest virus relief package that lacks elements of the Democrats’ preferred HEROES Act bill. Cunningham said there are a lot of positive items in the Senate bill but it doesn’t go far enough.

“In a crisis you don’t go for perfect you go for good steps in the right direction,” Tillis said at a Raleigh television studio, adding that Cunningham “for every provision of the bill but for the fact that he would vote against it.”

But Cunningham, a Raleigh attorney and Iraq War veteran, blamed Tillis for failing to act after the first time he was briefed on the virus in late January.

“I think that we are seeing and experiencing an unprecedented failure of leadership in this country,” he said. “By his own admission, Sen. Tillis did nothing for over a month.” But Tillis countered by saying the January briefing still raised uncertainty about the virus’ danger.

The two candidates also differed over their confidence in an upcoming COVID-19 vaccine.

Cunningham said he would be concerned about receiving a vaccine should it be available by the end of the year unless many questions were answered, especially by the U.S. Food and Drug Administration. He said he's worried about the influence of politics and big money in Washington in the decision-making related to public health.

“Yes, I would be hesitant, but I'm going to ask a lot of questions. That would be incumbent upon all of us,” Cunningham said. He told reporters afterward that he would take the vaccine if the public health officials sign off on its efficacy.

Tillis jumped on Cunningham's uncertainty over the vaccine, saying a vaccine won't be released without meeting the FDA's standards.

“In the middle of a crisis you don't undermine an effective process of the FDA,” Tillis said. “That statement puts lives at risk and it makes it more difficult to manage a crisis that he pretends to say ... he's up to the task to manage.”

Cunningham’s campaign has outraised Tillis for two consecutive quarters, and both sides should have little problem getting messages out in the final weeks. Tillis and Cunningham already have been the subjects of $47 million in outside spending during the campaign. Tillis’ campaign manager said this week that Democratic and Republican groups have reserved $93 million in TV ads from now until Election Day.

Polls showing Cunningham with a slight lead this summer have narrowed as Tillis and allies have criticized Cunningham for a 2001 legislative vote that raised taxes. Tillis pointed that vote out again Monday, and also accused Cunningham of misleading the public about his work at a company that received a Paycheck Protecting Program loan. Cunningham dismissed these and other accusations as exaggerated and misleading.

Both Cunningham and Tillis said they trusted mail-in absentee voting. Tillis said he had requested his absentee ballot a few weeks ago and encouraged all voters to do so. Tillis' comments contrast with Trump('s criticism of mail-in voting. The president has said who vote early by mail should vote again at their polling place if their ballot hasn’t been counted. Election officials have said that would lead to chaos at polling sites.

Cunningham said he would still vote in person during the early-voting period that begins Oct. 14.

Outside journalists weren’t permitted to watch the debate within the television station due to safety concerns from COVID-19. The moderator said he and the candidates entered the studio with masks and were properly distanced. Additional TV debates are set for Sept. 22 and Oct. 1.