TikTok is working on a deal with the Biden administration that would "fully safeguard" the app in the U.S. and quell fears about the Chinese government's accessing Americans' data, according to a letter TikTok sent to nine Republican senators that was released on Friday.

Shou Zi Chew, TikTok's chief executive, wrote that the company is nearing a final agreement with the U.S. government to ensure its data-sharing practices do not raise national security concerns.

As part of that arrangement, TikTok says all U.S. user traffic is now being routed to servers controlled by California-based Oracle, rather than TikTok's own infrastructure. Soon, he said, TikTok hopes to delete all U.S. data from the company's servers and rely completely on Oracle's storage "with access limited only to authorized personnel, pursuant to protocols being developed with the U.S. Government," Chew wrote.

Employees of Beijing-based ByteDance, which owns TikTok, can access data on the app, Chew wrote to the senators. The company has acknowledged before that some employees can gain access to U.S. user data, but the letter added new detail.

For instance, the data foreign employees can view is a "narrow set of non-sensitive TikTok user data," including public videos and comments left on videos, Chew wrote. He said none of that data is shared with Chinese government officials and ByteDance employees can only see Americans' TikTok data after an approval process overseen by the U.S.-based security team.

This system is in place to prevent possible requests from Chinese authorities. TikTok has long said Beijing has never sought Americans' information through TikTok, but the possibility has placed the hugely popular video app in the crosshairs of Washington lawmakers.

Republican senators, including Marsha Blackburn of Tennessee, raised new alarms about TikTok following a recent BuzzFeed report detailing the kind of access China-based employees have to Americans' data.

And Federal Communications Commissioner Brendan Carr recently urged Google and Apple to remove TikTok from its app stores for posing a serious national security threat. Carr worries the Chinese Community Party could get its hands on Americans' sensitive personal information.

"In fact, they came out and said that, well, of course, some of the data is accessed there. But it's only on an as-needed basis. And the definition of 'as needed' when it comes to entities beholden to the CCP is very, very different than, I think, what you or I would conceive of in terms of 'as needed,'" Carr said in an interview on Thursday with NPR's Morning Edition.

The Committee on Foreign Investment in the U.S., a group led by the Treasury Department and including top officials such as those from the Departments of Justice and Homeland Security, continues to work with TikTok on safeguards that satisfy U.S. authorities.

TikTok, which has more than 1 billion active users around the globe, is the first global social media hit to come out of China. Despite being its largest market, it has had a bumpy ride in the U.S.

The Trump administration launched an all-out war on TikTok, attempting to have the app shut down in the U.S. unless it fully spun off from ByteDance. His administration announced an ownership deal with Oracle and Walmart that would have moved TikTok's headquarters to the U.S., but the deal was ultimately scuttled.

While the Biden White House has not followed its predecessor's scorched-earth approach, the administration has continued national security negotiations with the company to make sure the data of Americans is safe.

Some of the Republicans to whom TikTok addressed the letter were unsatisfied with its contents. Blackburn is calling on TikTok leaders to return to Washington for public testimony before Congress.

"TikTok's response confirms that our fears regarding CCP influence within the company are well-founded," Blackburn said in a statement. "They should have come clean from the start but instead tried to shroud their work in secrecy. Americans need to know that if they are on TikTok, Communist China has their information."