New York(CNN Business) Advertisements for face masks continue to appear on Facebook (FB) almost two weeks after the company pledged to ban marketing for the medical gear hospitals are in dire need of.

That is according to research compiled by two consumer groups, the Coalition for a Safer Web and Digital Citizens Alliance.

Public officials have said the advertisements contribute to the nationwide shortage of face masks which are essential for medical professionals to have as they treat people for the novel coronavirus.

Facebook pledged on March 6 that it would forbid advertisements for masks, promising that it would "begin to enforce this change over the next few days."

But such promotions have continued to appear on the platform.

The Coalition for a Safer Web and the Digital Citizens Alliance have found such advertisements showing up on Facebook in recent days. The Digital Citizens Alliance sent a letter to the Department of Justice with its findings on Thursday.

Attorney General William Barr has urged the Justice Department to prioritize investigations of fraudsters and hackers exploiting the coronavirus pandemic.

One paid advertisement for a purportedly "FDA accredited" mask was found Tuesday by researchers from the Coalition for a Safer Web. Another advertisement the group spotted Monday told Facebook users the masks could, "Safeguard you and your family from COVID-19."

Rob Leathern, the director of product management at Facebook who is responsible for the advertisements team, appeared to acknowledge Wednesday night that Facebook's systems still need improvement.

"We have been preparing for more automation catching these ads, but it is not there yet," Leathern said when asked on Twitter by CNN Business why an advertisement for an "N95 Face Mask" was served to one user.

That advertisement, which journalist Colin Jones said Facebook served to him on Tuesday, contained text for two key terms that Facebook's systems would have ideally caught: "N95" and "Face Mask."

Pressed further on that specific advertisement, and why Facebook failed to catch it nearly two weeks after announcing it would prohibit such promotions, Leathern said, "We don't typically share specifics on any mechanisms since bad actors attempt to get around them, but it takes time for algorithms/reviewers to train + roll out enforcement."

"I wish it were as simple as turning on a switch but alas it is not," Leathern added. "Like I said, you'll start seeing the enforcement crank up and we will share more updates on our progress here soon."

Leathern did say that Facebook had taken down "many tens of thousands" of advertisements in violation of its new policy. But he added, "We will see more until we completely roll out."

In the meantime, Leathern asked people to report advertisements breaking the policy to Facebook and his team.

Andy Stone, a Facebook spokesperson, told CNN Business Thursday that full-scale enforcement of the policy will begin next Monday. This means that the issues about enforcement and automation Leathern wrote about on Wednesday will begin to be addressed Monday, he said.

Facebook isn't the only technology giant that has struggled to enforce its new ban on face mask advertisements.

Two Democratic senators on Tuesday asked the Federal Trade Commission to pursue enforcement action against Google saying the company is continuing to allow advertisements for the sale of face masks amid the coronavirus pandemic.

Sens. Mark Warner of Virginia and Richard Blumenthal of Connecticut said that despite Google announcing a ban on advertisements for protective facemasks last week, their staffs were easily able to find Google ads for facemasks over the past week.

The senators argued the advertisements contribute to the shortage of products essential to heath care workers on the frontlines of the United States' coronavirus response.

Asked for comment on the letter, a Google spokesperson said at the time, "We're committed to protecting users and surfacing helpful, authoritative information as the coronavirus situation continues to evolve."

"Since January," the Google spokesperson added, "we have blocked millions of ads that attempted to capitalize on coronavirus and have implemented a temporary ban on all medical face mask ads. We continue to take action to protect users and prevent these ads from serving."