If you’re a Cuban American wanting to visit Cuba, be careful! The Cuban government could seize your U.S. passport, or even draft you or your children into the armed forces.

And that’s not a warning from opponents of the Obama administration’s ongoing thaw in relations with Havana. It comes straight from the U.S. Embassy in Havana.

A statement on the embassy’s official web page warns that the Cuban government “does not recognize the U.S. nationality of U.S. citizens who are Cuban-born or are the children of Cuban parents.”

It adds that those people “will be treated solely as Cuban citizens” and that the Cuban government also can demand that they enter the island using their Cuban passports instead of their U.S. documents.

Those visitors also “may be subject to a range of restrictions and obligations, including military service,” and may have their passports confiscated, the Embassy added. Cuba has a mandatory military service system, in which everyone is supposed to serve 14 to 24 months when they turn 16.

“There have been cases of Cuban-American dual nationals being forced by the Cuban government to surrender their U.S. passports,” added the undated statement, posted on the Embassy’s web page.

As if the risk of being stuck in Cuba were not enough, the statement also warned about “Cuba’s denial of consular services to dual American-Cuban nationals who have been arrested.”

William Cocks, a spokeperson for the Bureau of Consular Affairs at the U.S. Department of State, told el Nuevo Herald that the travel warning is not new and that the information has been posted on a State Department website page since October 2015. Embassies often use the same information, and travel warnings are issued on a regular basis, he said.

The U.S. Embassy in Havana did not immediately respond to questions about the travel warning.

Cocks also said that the information about the children of Cuban Americans being considered Cubans when they visit the island comes from “experience” and “how we understand that the government of Cuba deals with U.S. citizens of Cuban origin.”

The concerns triggered by the statement, which has been making the rounds on social media platforms in recent days, come at a time when U.S. travel to the island, especially by Cuban Americans, is growing quickly because of the Obama administration’s new policy of “engagement,” which promotes trips to the island as an essential part of improving bilateral relations.

About 390,000 U.S. citizens of Cuban background visited the island in 2015. The Cuban Ministry of Tourism reported that 116,000 Cuban Americans and 94,000 U.S. citizens visited in just the first four months of this year alone.

The Cuban government’s decision to treat some Cuban Americans as Cubans is paradoxical because the island’s constitution, in Article 32, says that “dual citizenship will not be allowed. In consequence, when a foreign citizenship is acquired, the Cuban one will be lost.” That means Cubans who have become U.S. citizens legally lost their Cuban citizenship and should be able to use their U.S. passports when they return to the island — a long-standing demand by Cuban Americans now highlighted by the controversy sparked by the Carnival cruise ship that sailed from Miami to Cuba.

Even more surprising is the Embassy’s warning that the U.S.-born children of Cuban parents may also be treated as Cuban citizens if they visit the island. Cuba currently allows them to visit using their U.S. passports and Cuban entry visas, but may risk arbitrary decisions by the Cuban government, the diplomatic mission indicated.

Grisel Ybarra, a Cuban-American lawyer who specializes in immigration cases, said the Cuban constitution is similar to some European constitutions because it awards citizenship based on parental as well as geographical factors. Foreigners also can become naturalized Cuban citizens.

Article 29 says Cuban citizens are those “born abroad of a Cuban father or mother, as long as the legal requirements are met,” as well as “those born outside the national territory, of Cuban fathers or mothers who have lost their Cuban citizenship, as long as they request it (the Cuban citizenship) in the manner required by law.”

Although most Cuban Americans do not undertake the requirements for their children to retain or obtain Cuban citizenship, Ybarra added, that does not rule out the possibility that authorities on the island could consider the children to be Cuban citizens.

Ybarra said she had a client whose wife decided to stay to live in Cuba during a family visit to the island. Although the Cuban-born couple had both become U.S. citizens, and one of their three children had been born in the United States, Cuban authorities regarded the children as Cuban citizens, meaning that both parents had to approve any trips abroad for the kids. The wife refused to approve, and there was little the lawyer could do.

The U.S. Embassy statement suggests reading its section on Children’s Issues “for information on how dual-nationality may affect welfare inquiries and custody disputes.” The section, however, is not yet available online.

On the other hand, Cuban Americans are not always considered to be Cuban citizens. When it comes to medical treatment, the embassy statement added, Cuban Americans cannot go to the free public hospitals used by Cubans living on the island. They are required to seek treatment in clinics reserved for foreigners, where they pay high prices.

The statement also warns that dual U.S. and Cuban citizens “should be especially wary of any attempt by Cuban authorities to compel them to sign ‘repatriation’ documents.

“In several instances, the Government of Cuba has seized the U.S. passport of dual nationals signing declarations of repatriation and has denied these individuals permission to return to the United States,” the embassy said.

The Cuban Embassy in Washington did not respond to requests for comment for this story.