(CNN)Joe Biden says he and his campaign "continue to feel very good" about the Democratic nominee's prospects of winning the presidency as votes are counted in several key states.
The former vice president said he and his running mate, California Sen. Kamala Harris, have "no doubt" that after votes are counted, the two "will be declared the winners."
But, he said: "Stay calm. The process is working. The count is being completed. And we'll know very soon."
Biden's comments in Wilmington, Delaware, on Thursday came after he attended a briefing on the coronavirus pandemic -- and amid a series of lawsuits and complaints from President Donald Trump's campaign as votes cast by mail are counted.
Biden currently has won 253 electoral votes, according to CNN projections. Winning Pennsylvania or two of the three states of Arizona, Georgia and Nevada would deliver him the presidency.
"Each ballot must be counted, and that's what we're going to see -- going through now. And that's how it should be," Biden said. "Democracy is sometimes messy. It sometimes requires a little patience, as well. But that patience has been rewarded now for more than 240 years with a system of governance that is the envy of the world."
Biden's comments came hours after his campaign manager ihad nsisted that the Democratic nominee is on pace to win the presidency, but urged patience as Arizona, Georgia, Nevada and Pennsylvania continue counting votes.
"Our data shows that Joe Biden will be the next president of the United States," Jen O'Malley Dillon told reporters in a briefing late Thursday morning. "Donald Trump continues to push a flailing strategy designed to get people's votes from being counted."
In the briefing, O'Malley Dillon walked through each of the states where votes are still being counted and the outcome is unclear.
She said she is "looking for that moment" Thursday when additional results from Georgia and Pennsylvania -- particularly in Atlanta, Philadelphia and their surrounding areas -- push Biden ahead of Trump, who holds slim leads in both states.
O'Malley Dillon was optimistic about Pennsylvania, where she said Biden "will win by a sizable number of votes," and said Georgia is "very, very close" but "at this stage leans toward" Biden.
"We don't really care which state takes us over the top. We just want to keep going and make sure the counts get done," O'Malley Dillon said. "We know that it's going to take a little bit of time and we support that, and we're just going to stay calm and be patient."
She said she thinks Biden's narrow leads in Arizona and Nevada could shrink during the day Thursday, as votes from rural areas that favor Trump are added to their tallies. But results from more urban areas that are more favorable to Biden are expected to follow those, she said.
In Arizona, she said, Maricopa County -- the home of Phoenix -- will report results late Thursday night and potentially again Friday. Pima County, which is even more favorable to Biden, does not plan to report more results until Friday.
"We will win by tens of thousands of votes but that margin will close" in Arizona, she said.
CNN has not projected a winner in Alaska or North Carolina, but O'Malley Dillon did not express confidence in either state.
Biden campaign senior adviser Bob Bauer slammed the lawsuits filed by Trump's campaign, saying they are part of a "broader disinformation campaign" and "political theater."
"All of this is intended to create a large cloud, that it is the hope of Trump campaign that nobody can see through," Bauer said. "But it is not a very thick cloud, it's not hard to see what they're doing. We see through it. So do the courts. And so do the election officials."
