Kamala Harris celebrated her 60th birthday on the campaign trail on Sunday while Donald Trump doubled down on his dangerous rhetoric labeling Democrats as “enemies from within,” as both candidates tried to shore up support in key states ahead of the US presidential election.

Harris rallied Black voters in Georgia on Sunday with “souls to the polls” visits to two community churches.

Harris’s comments to the congregation of the New Birth Missionary Baptist church in Atlanta focused on how religious experiences in her youth in Oakland, California, influenced her politics. Drawing on the parable of the Good Samaritan in the Gospel of Luke, the vice-president argued for policies that embrace compassion.

She said: “When we come across our brothers and sisters in need, let us, as the Good Samaritan, did see in the face of a stranger, a neighbor, and let us recognize that when we shine the light in moments of darkness, it will guide our feet into the path of peace.

“And let us remember that while weeping may endure for a night, joy cometh in the morning.”

She asked: “What kind of country do we want to live in – a country of chaos, fear and hate, or a country of freedom, compassion and justice?”

Harris added: “The great thing about living in a democracy is that we, the people, have the power to answer that question. So let us answer not just through our words, but through our actions and with our votes.”

Later in the day, Stevie Wonder joined Harris at a rally at the Divine Faith Ministries International in Jonesboro. The vice-president was also set to tape an interview with the civil rights leader the Rev Al Sharpton, to be broadcast later Sunday on MSNBC.

Trump, meanwhile, doubled down on his earlier comments that attacked Democrats as “the enemy from within”, this time specifically denouncing representatives Nancy Pelosi and Adam Schiff.

During an interview with Howard Kurtz on Fox News, broadcast on Sunday, the former president said that “radical left lunatics … the enemy from within … should be very easily handled, if necessary, by the national guard, or if really necessary, by the military” – before singling out Pelosi and Schiff.

Similar comments made by Trump in the past weeks have sparked widespread concern and raised fears of an authoritarian crackdown if he were to become president again. The Harris campaign was quick to respond to the new comments.

“Even in his Fox News safe space, Donald Trump cannot help but show himself as the unhinged, angry, unstable man that he is – focused on his own petty grievances and tired playbook of division,” Ammar Moussa, a Harris-Walz campaign spokesperson, wrote in an email.

“This is precisely why his handlers are hiding him from major mainstream interviews and refusing to let him debate again. They don’t want the country to see this candidate in decline,” he added.

Also taking the stage on Sunday was Elon Musk, the billionaire owner of X who has thrown his weight behind Trump. Musk attended a town hall at the Roxian Theater in Pittsburgh, carrying a yellow “terrible towel” of the Pittsburgh Steelers, the city’s beloved NFL team, and jumping up and down as the crowd chanted his name.

In a short speech, Musk repeated false and fear-mongering claims, telling attendees “the constitution is literally under attack”.

He then issued his second check for a million dollars to a signatory of his petition backing the first and second amendment.

Musk announced on Saturday that America Pac, his Trump-allied political action committee, will give $1m every day until the presidential election to someone who signs the petition. The pledge appears to be a way to incentivize Republicans in battleground states to register to vote.

And also on Sunday, Democratic governors from three states in the so-called blue wall that is key to their party’s aspirations for an electoral college victory delivered their closing pitches for Harris.

Josh Shapiro of Pennsylvania, Tony Evers of Wisconsin and Michigan’s Gretchen Whitmer barnstormed the Sunday morning political shows to talk up the vice-president’s policy agenda – and highlight differences with Trump, 16 days before an election that polls suggest is still on a knife edge.

“I don’t want to go back to Donald Trump when he was in charge of the country,” Shapiro told NBC’s Meet the Press.

“Remember the record? I know there’s still some people that have maybe a little brain fog, they don’t remember what it was like under Donald Trump. You had more chaos, you had less jobs, and you had a whole lot less freedom.

“I don’t think we want to go back to a time of chaos. I want a stable, strong leader, and that’s Kamala Harris.”

“Both candidates believe that Pennsylvania is critical – I just think we’ve got a better candidate, a better message, and what we’re experiencing is a whole lot more energy,” Shapiro said.

In Michigan, according to Whitmer, voters were comparing both candidates’ records ahead of the 5 November election.

“While this is going to be close, I’d much rather be playing our hand in theirs,” she said. “We got a better candidate. We’ve got receipts on the issues that matter to the American people, on the economy, individual rights, affordable housing, and we got a better ground game.”

It also emerged Sunday that Harris has no plans to campaign with Joe Biden before election day on 5 November, a development appearing to confirm recent reports of friction between the two after the 81-year-old president was pressured out of running for re-election over age-related questions.

“The most important role he can play is doing his job as president,” an anonymous White House official told NBC News, which said the decision was mutual following discussions between the campaign and Biden administration officials.

Republicans appearing on the Sunday talk shows attempted to detract from Trump’s comments and other recent behavior, including suggesting in an interview this week he would use the US military against political enemies.

Republicans, meanwhile, were trying to control the message after Trump’s extraordinary and vulgar rhetoric during a Saturday night rally in Pennsylvania, when he called Harris a “shit vice-president” and exalted the size of the late golfer Arnold Palmer’s penis.

The South Carolina senator Lindsey Graham lost his composure when questioned about it on NBC’s Meet the Press – and tried to pivot to two recent assassination attempts on Trump, both conducted by pro-Republican persons.

“When you talk about rhetoric, you gotta remember they tried to blow his head off,” Graham said. “And another guy tried to kill him … so I’m not overly impressed about the rhetoric game here.”

Graham also condemned Republican colleagues, including Liz Cheney and Adam Kinzinger, as well as numerous ex-Trump administration officials who have denounced him and expressed support for Harris.

The House speaker, Mike Johnson, was more restrained – but equally as determined to avoid questions about Trump’s commentary in an appearance on CNN’s State of the Union, suggesting that it was host Jake Tapper who was obsessed with talking about Palmer’s penis.

“The media can pick it apart, but people are going to vote what’s best for their family and they see that in Trump,” he said.

Early in-person voting is under way in numerous states, with voters in Georgia setting a first-day turnout record on Tuesday, even as polls have the candidates in a virtual dead heat.