BEIJING — To the growing list of entities questioning the ownership of Anbang Insurance Group, the Chinese financial conglomerate, add one more: an American hotel union.

The union, Unite Here, said in a statement on Thursday that it had filed federal unfair labor practice charges against Anbang and three hotels it owns in the United States for failing to comply with its request for information on the company’s ownership and sources of financing.

The union — which represents more than 1,000 workers at Anbang’s Westin St. Francis hotel in San Francisco, the Loews Santa Monica hotel in California and the Fairmont Chicago hotel — had asked Anbang and its hotel operators for that information as well as for documents related to potential condominium conversions of hotels in May. It said the companies had not responded.

“By filing these federal charges, we’re asking the National Labor Relations Board to compel disclosure,” said Kurt Petersen, a co-president of Unite Here Local 11, a Los Angeles affiliate.