WASHINGTON – President Donald Trump said Wednesday that an American woman who was the bride of an Islamic State fighter and now wants to come home will not be allowed back in the United States.

“I have instructed Secretary of State Mike Pompeo, and he fully agrees, not to allow Hoda Muthana back into the Country!” Trump wrote on Twitter.

Muthana traveled to Syria and married and had a child with an ISIS fighter and now wants to face the U.S. justice system.

But Pompeo said earlier Wednesday that Muthana is not an American citizen and "does not have any legal basis, no valid U.S. passport, no right to a passport," contradicting statements by her family and her Florida-based lawyer, who said she was born in Hackensack, New Jersey, in 1994.

Muthana, who was raised in Alabama, left the United States to join ISIS four years ago at age 19. In Syria, she called for Americans to be attacked, and she spread the group's propaganda online.

She is one of about 1,500 foreign women and children – the spouses and children of Islamic State militants – held in a Kurdish-run detention camp in northern Syria.

Muthana is there with her 18-month-old son.The child's father is not alive. Two of her previous husbands, both Islamic State militants, are also dead. Muthana is not allowed to leave the camp and has armed guards protecting her from Islamic State sympathizers. She is asking to be allowed to return to the U.S. to face due process.

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"The government needs to engage with her, but not just her; all of these people who joined ISIS" from the West, said Hassan Shibly, Muthana's lawyer.

"If she broke the law, then the justice system can deal with her, and if she didn't break the law, she should come back anyway, so it can be determined if she is a threat."

More:American, British ISIS brides Hoda Muthana, Shamima Begum plead to go home

Shibly said Muthana has realized she made a mistake in moving to Syria and wants to return to the USA to face justice and "pay any debts she has to society." He said she wants to speak out against the Islamic State and help de-radicalize other Americans.

Muthana abandoned her family and fled to Syria in 2014, a year after she graduated from high school. She briefly studied at the University of Alabama-Birmingham.

Shibly shared a letter Muthana wrote this week in which she described herself as "naive, angry and arrogant" when she decided to journey to Syria.

"During my years in Syria, I would see and experience a way of life and the terrible effects of war, which changed me," Muthana wrote. "Seeing bloodshed up close changed me. Motherhood changed me. Seeing friends, children and the men I married dying changed me. Seeing how different a society could be compared to the beloved America I was born and raised into changed me."

Shibly, executive director of the Florida Council on American Islamic Relations in Tampa, said it was not clear from a legal standpoint whether Muthana's "marrying into ISIS" could warrant a "material support charge" to Islamic State activities, which range from terror attacks in the USA and Europe to beheadings in Iraq and Syria.

Alan Dershowitz, a former Harvard law professor, said that if he were advising Muthana, he would tell her that coming back to the USA would be "risky." Dershowitz told the New York Post her case would be a "close call" even if all she did was tweet and send emails.

Muthana claimed to have had no contact with U.S. authorities, and Shibly said she can leave the camp only if the U.S. government asks for her release. It's not clear if it has. U.S. immigration authorities were not available to answer questions about her case, including whether a U.S. citizen can be barred from entering his or her own country.

In a briefing, State Department spokesman Robert Palladino would not address Muthana's specific case, but said repatriating foreign terrorist fighters to their countries of origin was the "best solution to preventing them from returning to the battlefield."

Pompeo subsequently issued the statement Wednesday in which he claimed that Muthana was not a U.S. citizen and would not be allowed back in.

Shibly, however, provided USA TODAY with a copy of Muthana's birth certificate, which lists her place of birth as Hackensack, New Jersey.

Steve Vladeck, a law professor at the University of Texas, said that Pompeo can't just assert that someone born in the U.S. is not a U.S. citizen.

"I gather that the government's argument is that she was born to a diplomat who was in the United States on official business, and so was not entitled to birthright citizenship. That's correct as a matter of law if it's true, but it's not true just because the government says so," he said in a Twitter message to USA TODAY.

Only six American militants have returned from fighting or training with militant groups in Syria, according to New America, a Washington-based foreign policy research institute.

All were taken into custody. Muthana may be the first American spouse or partner of an Islamic State fighter who has sought to return home. The New York Times has reported that another woman, dual U.S.-Canadian national Kimberly Gwen Polman, 46, is also in the al-hawl refugee camp in Syria. She left Canada in 2015.

A similar case in Britain involves Shamima Begum, 19, from London, who gave birth to a baby boy over the weekend in the same camp where Muthana is held.

Begum, who left Britain for Syria at age 15 and married an Islamic State fighter, wants to return to Britain for the sake of her child's welfare, but British authorities, including the nation's interior minister, indicated they might try to block her return. They might find that difficult to do because a British national can't theoretically be prevented from returning home unless that person is also a national of another country. Begum isn't.

The woman's London-based lawyer, Tasnime Akunjee, said Tuesday that the British government informed him that it is trying to strip Begum of her British citizenship.

As for Muthana, "whether it's a few years in jail, 20 years in jail or no jail, she's open to the legal process, and she's not asking for a free pass, just due process," Shibly said.