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BARCELONA, Spain — In front of a packed audience here, Mark Zuckerberg turned on the charm.

The Facebook chief executive outlined on Monday why he thought Internet.org, a service backed by his company that is intended to provide people in emerging markets with free access to some online applications, would help telecommunications carriers persuade customers to spend more on streaming content to their cellphones.

The service, which is now offered in countries including Paraguay and Zambia, allows individuals to access Facebook and a limited number of other applications free. Carriers hope that this access — often the first time that people have surfed the web — will lead them to spend money on separate data packages.

‘‘Growing the Internet is expensive work,’’ Mr. Zuckerberg, dressed in jeans and a gray T-shirt, told an audience at the Mobile World Congress, an industry conference that has become an annual global event where telecom operators talk shop. ‘‘The only way to accelerate that is to help operators to grow their business.’’

Mr. Zuckerberg’s words are part of efforts to quell growing disquiet among some carriers, particularly in Western countries, who say that Facebook, Google and other Internet companies are taking unfair advantage of carriers’ mobile networks.

Industry executives say that these Internet services, which are used by billions of individuals each day, do not invest in the costly infrastructure required so that people can access applications on their smartphones. Some also say that the likes of Facebook, which now holds a strong position in Internet messaging after buying WhatsApp last year for $19 billion, do not face the same tough regulations as traditional operators.

‘‘We want a level playing field,’’ Vittorio Colao, Vodafone’s chief executive, said in Barcelona on Monday. ‘‘Facebook now has become one of the biggest Internet messaging companies in the world.’’

Mr. Zuckerberg tried to assuage these concerns, saying that Facebook helped drive extra revenue to carriers because people were willing to pay extra to access online services.

‘‘The business of operators used to be voice and messaging, but that has shifted towards data,’’ Mr. Zuckerberg said. ‘‘Apps like Facebook drive data usage, and that’s the future of the business.’’

And after Google announced earlier on Monday that it was working on partnerships with carriers to offer its own mobile services, Mr. Zuckerberg reiterated that he would be willing to work with the search giant on potential deals, primarily in emerging markets. Both Silicon Valley companies have announced projects, including blimps equipped to provide Wi-Fi access to the Internet across broad areas, that are intended to bring online services to developing countries.

‘‘We would love to do more with them,’’ Mr. Zuckerberg said when asked about potential agreements with Google.

As part of his charm offensive, Mr. Zuckerberg was joined on stage Monday by executives from several emerging market carriers that have become partners of Internet.org.

Christian De Faria, chief executive of Airtel Africa, one of Facebook’s partners, said he was initially skeptical about joining the Internet.org initiative.

‘‘One year ago, if you had asked me about Facebook, I would have said it was like beauty and the beast,’’ Mr. De Faria told the conference, adding that his carrier had seen an increase in paid data traffic since joining Internet.org. ‘‘But I can say that the beast has become more human.’’