Superfast 5G wireless service is slowly rolling out across the country, but Verizon TV ads have exaggerated the progress, a top advertising watchdog said on Tuesday.

“To the extent Verizon wishes to promote the current availability and performance of its 5G network to consumers across the nation—including people who live in cities and towns across the country that may not receive Verizon 5G coverage for months, if not years—Verizon should ensure that its advertising clearly and conspicuously communicates to consumers the relevant, material limitations of its current network,” the National Advertising Division of BBB National Program concluded after reviewing the carrier’s TV spots.

Verizon’s new 5G service, which can provide downloads at speeds 10 to 100 times faster than the average 4G LTE connection, is available only in parts of 35 cities, with the carrier aiming to reach 60 cities by year-end. In a Fortune review of the new Lenovo Flex 5G laptop, Verizon’s 5G network hit download speeds of almost 2 gigabits per second in one location in Boston but dropped to a 4G connection of 98 megabits per second a few feet away. Nationwide, Verizon customers found 5G connectivity only 0.4% of the time in the U.S. in June, according to a report from Opensignal.

That was the kind of limited availability that was overlooked by Verizon’s TV commercials, according to the NAD’s findings. The industry self-regulator said Verizon should remove from its ads phrases such as, “People from Midtown Manhattan to downtown Denver can experience what your 5G can deliver” and discontinue any claims that imply “that its 5G service is widely available in cities across the country, and that its service is broadly and readily accessible in cities where it has been launched.”

Verizon told the NAD that it did not agree with all aspects of the decision but that it will comply with the recommendations. The carrier added that it “remains committed to the self-regulatory process and believes strongly in transparency of customer messaging.”

The TV ads in question stopped running months ago, a Verizon spokesman told Fortune.

Verizon is hardly the only wireless carrier to face NAD’s wrath over exaggerated TV advertising claims. The unit criticized AT&T for using the phrase “5G Evolution, the First Step to 5G” to describe its 4G service. AT&T appealed to the National Advertising Review Board, which reaffirmed the critique in May. And T-Mobile was dinged in 2017 for saying its 4G LTE network was faster than Verizon’s.

(Correction: This story was corrected on July 14, 2020, to state that the National Advertising Division is part of the BBB National Program.)