Facebook, Google and Amazon bolstered their lobbying spending in the past three months as Washington has taken a closer look at the market power of some of America's biggest tech companies.

Facebook spent $2.85 million lobbying the federal government in the third quarter, up 41 percent from the same period last year, according to disclosure reports made public late Friday. Part of that amount was dedicated to lobbying officials in Congress and the White House on “online advertising, content and platform transparency efforts.” The lobbying comes as the social network, along with Google and Twitter, faces a new bipartisan push on Capitol Hill that would force Internet companies to disclose more information about political ads sold and distributed on their platforms.

The lawmakers behind proposed ad transparency legislation said the bill is designed to prevent another Russian-backed disinformation campaign that ran on an array of Web platforms during the 2016 election. Facebook said that it will take its own steps to increase the transparency of political ads and that it generally supports legislative efforts to do the same.

Google also increased its spending relative to last year, doling out $4.17 million on lobbying in the third quarter, up 9 percent. In addition to lobbying Congress and the White House on the regulation of online advertising, Google also used its lobbying operation for issues such as the Deferred Action for Childhood Arrivals program, President Trump's travel bans, and antitrust law and tax reform.

Of any corporation in or out of the tech industry, Google spent the second-highest amount. AT&T topped everyone, at $4.43 million. The telecom company is still waiting for federal officials to review its $85 billion proposed acquisition of Time Warner, which is listed on its lobbying disclosures. The two companies recently said they will extend the deadline to finalize the deal, with the hope of obtaining a nod from the government.

Google's uptick in lobbying comes as it faces the largest fine the European Union has ever levied against a company for abusing its dominant market position. This summer, the European Union's antitrust chief hit Google with a $2.7 billion fine for illegally steering users toward its comparison shopping site. Google is appealing the decision.

Antitrust was also a lobbying priority for Amazon, which listed the purchase of Whole Foods on its third-quarter disclosures. While that acquisition was approved without protest from antitrust officials, in recent months, some in Washington and Silicon Valley have called for increased scrutiny of the Internet's dominant platforms on the grounds that they may unfairly exploit their economic power.

Amazon, according to its disclosures, spent $3.4 million from July 1 to Sept. 30, up 26 percent from what it spent during the same period last year. That's more than Amazon has ever spent in a single quarter. Amazon lobbied on issues including DACA, autonomous vehicles and corporate tax reform.

Uber and Apple also increased their spending in the third quarter year over year. Apple spent $1.86 million in the third quarter, up 73 percent. The iPhone maker lobbied on issues including DACA, corporate tax reform and climate change. Uber dedicated $510,000 to federal lobbying, an increase of 50 percent. Autonomous driving and foreign regulation of data management were among the issues the ride-hailing company prioritized.

While many of tech's biggest names pumped up their lobbying spending, Twitter and Microsoft actually decreased their spending compared with the third quarter last year.

Facebook, Google, Apple, Amazon and Twitter declined to comment. Uber and Microsoft did not immediately respond to a request for comment.

(Amazon founder and chief executive Jeffrey P. Bezos owns The Washington Post.)