Apple and TikTok took a lashing Tuesday for skipping a congressional hearing meant to explore the tech industry and its ties to China, an absence that threatens to bring sustained political scrutiny of the companies’ controversial relationships with Beijing.

Two empty chairs at a witness table served to illustrate the companies’ absence from the hearing, convened by Sen. Josh Hawley (R-Mo.), a tech-industry critic who opened the session by blasting Apple and TikTok over “the danger of Chinese tech platforms’ entry into the U.S. market and the danger of American tech companies’ operations in China.”

Hawley reserved his most pointed criticism for TikTok, questioning whether the company — owned by ByteDance, a Chinese conglomerate — sufficiently protected U.S. users’ data and resisted the censorship demands of government officials in Beijing.

Hawley referenced reporting from The Washington Post that cited former employees saying they often felt pressure from officials at their Chinese headquarters to downplay videos deemed to be politically or culturally controversial. Hoping to address critics’ lingering fears, Vanessa Pappas, the company’s top U.S. official, told The Post that TikTok is “not directed by any foreign government, including the Chinese government.”

“TikTok claims they don’t take direction from China,” Hawley said. “They claim they don’t censor. … But that’s not what former employees of TikTok say.”

The criticisms come at a tough time for TikTok, which is facing investigation by the U.S. government over potential national security concerns. TikTok has maintained its independence, saying that U.S. users’ data is stored in Virginia with a backup in Singapore and that it does not make decisions about content moderation based on signals from Beijing.

Hawley also took aim at Apple, saying its ties to China are “risking compromise with authoritarianism.” He raised iCloud, the iPhone maker’s cloud storage service, which he said houses Chinese citizens’ data locally. Government rules require Apple to offer iCloud in this way, but Hawley said the setup could undermine users’ security, echoing concerns raised by some human rights and privacy advocates.

“We’re accustomed in hearings like this one to hearing about Apple as a good corporate citizen,” the senator said, citing the company’s privacy practices. “But Apple’s business model and business practices are increasingly entangled with China, a fact they would rather we think not too much about.”

Apple previously has said it advocated against the law but was unsuccessful. The company declined comment on the hearing, but pointed to its past statement on the matter: “Apple has not created nor were we requested to create any backdoors and Apple will continue to retain control over the encryption keys to iCloud data,” it said. “As with other countries, we will respond to legal requests for data that we have in our possession for individual users, never bulk data, and when we provide data, we will continue to include the requests in our semi-annual transparency reports.”

Apple has struggled with its own share of controversies involving China in recent months. In October, Apple removed an emoji for the flag of Taiwan, which China considers part of its territory, from operating systems for users in Hong Kong; it banned a news outlet from its App Store that had covered the Hong Kong protesters critically; and it removed an app from that portal that had helped those demonstrators avoid police crackdowns. Responding to concerns at the time, Apple said the app ultimately had served to help some “target and ambush police.”

The explanation did not sit well with Hawley, who retorted that Apple’s “corporate values won’t do much to protect you.”

David Crawshaw and Reed Albergotti contributed to this report.