Twitter on Thursday sent a letter to Satya Nadella, Microsoft’s chief executive, accusing the tech giant of improperly using the social media company’s data.

In the letter, which was reviewed by The New York Times, Twitter said Microsoft had violated an agreement over its data and had declined to pay for that usage. In some cases, the letter said, Microsoft had used more Twitter data than it was supposed to. Microsoft also shared the Twitter data with government agencies without permission, the letter said.

“Microsoft may have been in violation of multiple provisions of the agreement for an extended period of time,” Alex Spiro, the personal lawyer for Elon Musk, who owns Twitter, wrote in the letter to Mr. Nadella.

The letter may be a prelude to Twitter trying to charge Microsoft for its data. Mr. Musk, who bought Twitter last year for $44 billion, has said that it is urgent for the company to make money and that it is near bankruptcy. Twitter has since introduced new subscription products and made other moves to gain more revenue. In March, the company said it would charge more for developers to gain access to its stream of tweets.