WASHINGTON — In the days after lawmakers introduced legislation that could break the dominance of tech companies, Apple’s chief executive, Tim Cook, called Speaker Nancy Pelosi and other members of Congress to deliver a warning.

The antitrust bills were rushed, he said. They would crimp innovation. And they would hurt consumers by disrupting the services that power Apple’s lucrative iPhone, Mr. Cook cautioned at various points, according to five people with knowledge of the conversations.

The calls by Mr. Cook are part of a forceful and wide-ranging pushback by the tech industry since the proposals were announced this month. Executives, lobbyists, and more than a dozen think tanks and advocacy groups paid by tech companies have swarmed Capitol offices, called and emailed lawmakers and their staff members, and written letters arguing there will be dire consequences for the industry and the country if the ideas become law.

The bills, the most sweeping set of antitrust legislation in generations, take aim at Amazon, Apple, Facebook and Google by trying to undo their dominance in online commerce, advertising, media and entertainment. There are six bills in total, and if passed, they would empower regulators, make it harder for the tech giants to acquire start-ups and prevent the companies from using their strength in one area to form a grip in another.

Amazon’s top lobbyist, Brian Huseman, rarely speaks publicly about bills before there is a vote. But with the House Judiciary Committee expected to vote on the bills on Wednesday, he warned in a statement on Tuesday that the legislation “would have significant negative effects on the hundreds of thousands of American small- and medium-sized businesses that sell in our store and tens of millions of consumers who buy products from Amazon.”

Google’s senior vice president for global affairs, Kent Walker, has also made calls to lawmakers in recent days, and the company’s top lobbyist, Mark Isakowitz, has weighed in on how the bills would alter how people use the internet. “American consumers and small businesses would be shocked at how these bills would break many of their favorite services,” he said in a statement. A spokesman for Facebook, Christopher Sgro, said that antitrust laws “should promote competition and protect consumers, not punish successful American companies.”

Thirteen nonprofits, most of which have received funding from the tech giants, wrote a letter to lawmakers decrying two of the bills. NetChoice, one of the groups, hosted a public panel on Tuesday featuring Senator Mike Lee, Republican of Utah and a leading member of the Senate antitrust subcommittee, to cast skepticism on the proposals. A prominent Republican lobbyist and fund-raiser, Jeff Miller, has been trying to stanch the support for the bills within his party, reaching out to members of Congress on behalf of his tech company clients.

“In a way I’ve never seen before, they are fighting tooth and nail,” said Gigi Sohn, a distinguished fellow at Georgetown University’s Institute for Technology Law and Policy. “They consider these bills existential for them because they get at their business models.”

Apple declined to comment on Mr. Cook’s calls to lawmakers, including to Ms. Pelosi.

The companies, which have long faced accusations of holding too much power, are now scrambling to find their footing with Democrats in control of Congress and the White House. The administration has picked aggressive critics of Big Tech as top antitrust regulators, including Lina Khan, the new chair of the Federal Trade Commission whose work as a legal scholar laid the foundation for the current antitrust push.

In Congress, progressive Democrats focused on the market power of the companies have united with some Republicans accusing social media companies of political bias and censorship. Representative Ken Buck of Colorado, the ranking Republican of the Judiciary Committee’s antitrust subcommittee, co-sponsored some of the bills being considered and has brought along other Republican members to support the legislation.

But the antitrust issue — even with some agreement between parties — has created new fault lines.

Within the Republican Party, there are deep divides on the antitrust bills. Tucker Carlson, the influential Fox News host, has praised the bills and has pushed for the breakup of Big Tech companies. But Representative Jim Jordan, an Ohio Republican, and Mark Meadows, who was chief of staff to President Donald J. Trump, wrote in an opinion piece on Fox News’s website that the bills would give the Democratic administration more control over the tech companies.

“Democrats are weaponizing legitimate Republican anger about Big Tech’s abuses to encourage Republicans to support these bills,” they wrote. “But Republicans should read the fine print.”

A similar argument is being made directly to Republican members of Congress by Mr. Miller, the Republican lobbyist, according to a person familiar with his efforts. Mr. Miller, whose firm has been paid a total of more than $1 million over the last two years by Amazon and Apple, has been a top fund-raiser for many Republicans, including Mr. Trump and Representative Kevin McCarthy, the House minority leader, who has criticized the bills as empowering Biden appointees like Ms. Khan to crack down on companies.

The tech companies have tried to navigate the complicated new political landscape by focusing their lobbying efforts in part on the Democrats from California who have seats on the Judiciary Committee.

That group includes Representative Zoe Lofgren of California, a longtime member of Congress whose district includes parts of the tech hub of San Jose. She is concerned that some of the bills could expose the tech giants to unnecessary lawsuits and imperil the engine of the state’s economy, said one Democratic congressional staff member, and is planning to propose amendments to the bills on Wednesday that could address some of those issues.

Ms. Pelosi pushed back on Mr. Cook’s concerns about the bills, according to two people with knowledge of the conversations. When Mr. Cook asked for a delay in the Judiciary Committee’s process of considering the bills, Ms. Pelosi pushed him to identify specific policy objections to the measures, said one of the people.

Morgan Reed, the president of the App Association, a trade organization sponsored by Apple and other tech and telecom companies, said in a letter to lawmakers on Tuesday that breaking up platforms and “limiting the services they can provide for our member companies would harm your constituents.”

Another outspoken critic is the Chamber of Progress, a left-leaning trade group formed in March by a former Google executive, Adam Kovacevich.

“Tech had a very long political honeymoon,” Mr. Kovacevich said. “Many politicians and policymakers think that maybe they were too easy on tech for a long time, and now there is a countervailing desire to punish tech through either new laws or through regulatory action. And that is at odds with what consumers want.”

He drafted and organized support for a letter that was sent this week urging members of the Judiciary Committee to oppose two of the bills. It warned that the bills would hurt consumers, resulting in Amazon without Prime, the iPhone without text or phone capabilities preinstalled, and Google without Maps. The letter was signed by Mr. Kovacevich’s group and an unusual mix of 12 other organizations, including tech associations, free-market conservative outfits and consumer groups, most of which have received funding from Amazon, Apple, Facebook or Google.

Eli Lehrer, the president of the fiscally conservative think tank the R Street Institute, which signed the letter, criticized Republican supporters of the bills for turning their backs on their free market principles by “calling on the government to use its power to intervene directly against some of the most successful companies in our country’s history.”

The institute has received funding from Google, but Mr. Lehrer said the funding did not affect its stance on the legislation, as did representatives from other signatory groups.

Representative Pramila Jayapal, a Democrat from Washington and a co-sponsor of the bills, said the lobbying is “making our case that they have way too much power in terms of monopoly power and in terms of money and politics.”

“Small business and consumers have no hope of competing with this amount of money and power,” she said.

Nicholas Fandos contributed reporting.