Democratic presidential nominee Hillary Clinton began what she called a 100-day march to the election Friday with an effort to bridge the Democratic Party’s widening gulf with small-town and working-class voters in the key battleground states of Pennsylvania and Ohio.

“We know that if we’re smart about it, we can bring back jobs from China and other places,” Clinton said at the start of a three-day bus tour of those up-for-grabs states.

She and her running mate, Sen. Tim Kaine (Va.), also laid out a string of attacks on Republican nominee Donald Trump. His populist, blue-collar appeal has capitalized on a trend that has seen more lower-income and lower-educated whites turning away from national Democrats, setting up a battle in key states for what was once the working-class soul of the Democratic Party.

At an earlier rally in Philadelphia, Clinton mocked Trump’s signature promise to “make America great again,” telling a crowd at Temple University: “He doesn’t make a thing in America except bankruptcies.”

Trump, meanwhile, tore into Clinton and others who spoke at the Democratic National Convention this week in an angry series of tweets Friday morning, deriding Clinton’s speaking style and accusing her of lying about his positions. He also called former New York mayor Michael R. Bloomberg — who spoke forcefully against Trump at the Democratic convention — “ ‘Little’ Michael Bloomberg” and “a disaster.”

“Crooked Hillary Clinton made up facts about me, and ‘forgot’ to mention the many problems of our country, in her very average scream!” he wrote in one tweet.

In a video posted on Instagram and Twitter, Trump also suggested that former president Bill Clinton fell asleep during his wife’s acceptance speech Thursday night. In another tweet, he said that the “dishonest media didn’t mention that Bernie Sanders was very angry looking during Crooked’s speech,” referring to the senator from Vermont who was vanquished by Clinton in the primary contest.

In Philadelphia, Clinton said that it was “kind of overwhelming” to become the first woman to head a major party’s ticket. “I take deeply and with great humility the responsibility that this campaign imposes on us.”

The Democrats shifted from the pomp of a nominating convention that concluded with Clinton’s acceptance address Thursday night to what Kaine called “the part of the campaign I really like.”

“I don’t like wearing a tie that much,” he said of the bus tour through states that have become less friendly to Democrats.

Clinton and Kaine later toured a K’Nex Brands toy factory in this southeastern Pennsylvania town. The family business makes building sets sold in the United States and exported to China and other countries. The company uses non-union labor, which went unmentioned by either candidate.

Clinton pledged that in her first 100 days, she would “break through the gridlock in Washington” to push a jobs plan that would be the biggest investment in new jobs since World War II. It would focus on infrastructure, technology, clean energy and advanced manufacturing.

Watch Democratic presidential nominee Hillary Clinton's speech at the Democratic National Convention in Philadelphia. Clinton spoke about domestic policy, national security and beating Republican presidential nominee Donald Trump. (Video: Victoria Walker/The Washington Post;Photo: Michael Robinson Chavez/The Washington Post)

“I’m also going to pay special attention to those parts of our country that have been left out and left behind,” she said.

In Pennsylvania and Ohio, that often means small towns that have suffered a slow exodus of manufacturing and other jobs that do not require a college degree. Clinton and Kaine are stopping in a couple such places as well as cities including Pittsburgh and Cleveland, where service and professional jobs have filled some of the gap.

“I’m not satisfied with the status quo. I’m not telling you everything is peachy-keen,” Clinton said in Philadelphia. “We’ve made progress, but we have work to do if we’re to make sure everybody is included.”

Former president Bill Clinton and Kaine’s wife, Anne Holton, are joining the trip. The former president stood to acknowledge a swell of applause when his wife said that the foursome would “barnstorm America.”

“As of tomorrow, we have 100 days to make our case to America,” Hillary Clinton said to cheers.

She was invoking the Founders, and what she called their recognition that democracy requires participation and shared commitment, when she was briefly interrupted by a protester who shouted, “Hillary Clinton is a war criminal!” The man was drowned out by the crowd’s chants of “Hillary, Hillary.”

“They expected a raucous debate,” Clinton said, somewhat drily, when she resumed.

At the toy factory, she said she was pleased to have her husband along for the tour, because “he knows a little bit about making the economy work for everyone.”

An NBC News-Wall Street Journal-Marist poll in early July, before the presidential nominating conventions, put Clinton even with Trump in Ohio at 39 percent each among registered voters. Clinton trailed by 19 percentage points among whites without college degrees (30 to 49 percent), while she led by 5 points among white college graduates (39-34). She made up the ground with an 88-0 advantage among African Americans. The education gap in Ohio contrasts sharply with the 2012 election in the state — that year, GOP nominee Mitt Romney won white college graduates by 18 points (58-40) and non-college whites by 14 (56-42).

A Quinnipiac University poll from the same period found that 70 percent of non-college whites had an unfavorable view of Clinton, as did 60 percent of college-educated whites. But Trump’s negatives with white college grads were slightly larger than Clinton’s, at 65 percent. Among non-college whites, 51 percent had an unfavorable view of Trump.

Vice President Biden, a native of Scranton, Pa., scolded his party earlier this week for failing to connect with the white working class. He acknowledged Trump’s appeal among the kinds of people who have supported Biden throughout his political career.

“I think the Democratic Party overall hasn’t spoken enough to those voters. They’ve done the right thing for the voters [but] haven’t spoken to them,” Biden said Wednesday on MSNBC, ahead of his address to the Democratic convention.

Biden said he will campaign for Clinton and Kaine in Pennsylvania, Ohio and Michigan.

In Colorado, where polls show Trump behind, he held a campaign rally Friday afternoon, with thousands of supporters waiting in a mile-long line outside the Gallogly Events Center at the University of Colorado at Colorado Springs. Another campaign was held in Denver on Friday evening, culminating a frenzied week of rallies across the country seemingly intended to counterprogram the Democratic convention.

At the Colorado Springs event, Trump bragged to his supporters about television ratings showing that his prime-time nomination speech last week in Cleveland edged out Clinton’s Thursday night address in Philadelphia.

“I watched last night. I watched Hillary Clinton. What a sad, what a sad situation,” Trump said during the rally. “I watched her last night giving a speech that was so average.”

Trump also promised to escalate his already harsh attacks against Clinton.

When members of the audience started chanting “Lock her up!” — a phrase that has become ubiquitous at his campaign events — Trump told them he agreed with them. At the Republican National Convention last week, he seemed to dismiss the chants by telling supporters that they should focus on defeating her instead.

“You know what, I’ve been saying let’s just beat her on November 8. But you know what, you know what, I’m starting to agree with you,” he said. “You know what, I don’t have to be so nice anymore. I’m taking the gloves off.”

In reality, Trump has made comments for months on the campaign trail about Clinton belonging in prison.

DelReal reported from Colorado Springs. Abby D. Phillip and Scott Clement in Washington contributed to this report.