Italian officials said Thursday that they are investigating whether Apple and Samsung intentionally slowed down their older products to get consumers to buy new ones.

This is the first time Samsung has faced this accusation.

The investigation by the consumer protection authority — L’Autorità Garante della Concorrenza e del Mercato, or AGCM, in Italian — lends weight to a suspicion harbored by many smartphone owners for years: that old gadgets seem to slow down right as new ones come out. That smoldering suspicion was fanned into flames after Apple, in December, confirmed it had slowed down ­iPhones with older batteries to preserve their performance.

AGCM said in a statement on its website that the inquiry was prompted by customer reports and its preliminary research. Both indicated that Apple and Samsung had exploited problems with their phones’ components to reduce their performance and encourage people to buy new devices, the agency said. AGCM did not specify which models it was looking into.

Samsung denied the accusations. “Samsung does not provide the software updates to reduce the product performance over the life cycle of the device," the company said in a statement Friday. Samsung said it will "fully cooperate" with the Italian investigation "to clarify the facts."

Apple declined to comment on the investigation. The company has repeatedly said that it didn’t slow down older phones for the purpose of selling new ones. In December, it apologized for not telling consumers that its software will slow down some iPhones if it senses the batteries have degraded. Adjusting the performance that way, Apple said, will prevent the phones from shutting down un­expectedly.

Apple started offering consumers discounted battery replacements for $29 in January and said this week that an update will provide an option to turn off the phone-slowing software.

Apple's chief executive Tim Cook also underscored in an interview with ABC News this week that Apple’s only motivation was to ensure people’s phones were working properly.

AGCM said in its statement that it would investigate whether the two companies violated parts of the Italian consumer code that prohibit them from misrepresenting their actions and keeping information from consumers. The AGCM statement did not specifically mention iPhone batteries or offer details of why it was also looking into Samsung. It also did not say what penalties the companies may face if the agency decides they have broken the law.

AGCM could not immediately be reached for comment.

The agency has investigated both companies before. It tangled with Apple in 2012 over its AppleCare warranty program, alleging Apple was not making it clear that customers were paying for perks beyond a two-year warranty. A two-year warranty is already guaranteed under Italian law. Apple appealed the decision, but lost and had to pay a fine of roughly $1.2 million and place new notices on its promotional materials.

AGCM fined Samsung in 2017 for not being clear about an advertising promotion; Samsung Electronics Italy settled and paid a 3 million euro fine.

In addition to the Italian investigation, Apple is facing more than a dozen consumer lawsuits in the United States, Australia and Israel. The company also faces a criminal suit in France, where “planned obsolescence” — hurting existing products to make way for new ones — is illegal. And a South Korean consumer advocate group has filed a complaint with the government, but officials there haven’t said whether they will launch an investigation.