WASHINGTON — The Justice Department unveiled sweeping charges on Monday against the Chinese telecom firm Huawei and its chief financial officer, Meng Wanzhou, outlining a decade-long attempt by the company to steal trade secrets, obstruct a criminal investigation and evade economic sanctions on Iran.

The pair of indictments, which were partly unsealed on Monday, come amid a broad and aggressive campaign by the United States to try to thwart China’s biggest telecom equipment maker. Officials have long suspected Huawei of working to advance Beijing’s global ambitions and undermine America’s interests and have begun taking steps to curb its international presence.

The charges underscore Washington’s determination to prove that Huawei poses a national security threat and to convince other nations that it cannot be trusted to build their next generation of wireless networks, known as 5G. The indictments, based in part on the company’s internal emails, describe a plot to steal testing equipment from T-Mobile laboratories in Bellevue, Wash. They also cite internal memos, obtained from Ms. Meng, that prosecutors said link her to an elaborate bank fraud that helped Huawei profit by evading Iran sanctions.

The acting attorney general, Matthew G. Whitaker, flanked by the heads of several other cabinet agencies, said the United States would seek to have Ms. Meng extradited from Canada, where she was detained last year at the request of the United States.