Thousands of requests by men to bring in child and adolescent brides to live in the US were approved over the past decade, according to government data.
In one case, a 49-year-old man applied for admission for a 15-year-old girl, the data obtained by the Associated Press showed.
The approvals are legal as the Immigration and Nationality Act does not set minimum age requirements.
In weighing petitions for spouses or fiancees, US Citizenship and Immigration Services (USCIS) goes by whether the marriage is legal in the home country and then whether the marriage would be legal in the state where the petitioner lives.
But the data raises questions about whether the immigration system may be enabling forced marriage and about how US laws may be compounding the problem despite efforts to limit child and forced marriage.
Marriage between adults and minors is not uncommon in the US, and most states allow children to marry with some restrictions.
There were more than 5,000 cases of adults petitioning on behalf of minors and nearly 3,000 examples of minors seeking to bring in older spouses or fiances, according to the data requested by the Senate Homeland Security Committee in 2017 and compiled into a report.
Some victims of forced marriage say the lure of a US passport combined with lax marriage laws are partly fuelling the petitions.
Naila Amin, a dual citizen from Pakistan who grew up in New York City, was forcibly married at 13 in Pakistan and applied for papers for her 26-year-old husband to come to the country. She said:
Ms Amin, now 29, said she was betrothed to her first cousin Tariq when she was eight and he was 21. The petition was eventually terminated after she ran away.
She said the ordeal cost her a childhood. She was in and out of foster care and group homes, and it took a while to get her life on track.
"I was a child. I want to know, why weren't any red flags raised? Whoever was processing this application, they don't look at it? They don't think?" Ms Amin asked.
There is a two-step process for obtaining US immigration visas and green cards. Petitions are first considered by USCIS. If granted, they must be approved by the State Department. Overall, there were 3.5m petitions received from budget years 2007-17.
Over that period, there were 5,556 approvals for those seeking to bring minor spouses or fiancees, and 2,926 approvals by minors seeking to bring in older spouses, according to the data. Additionally, there were 204 for minors by minors. Petitions can be filed by US citizens or permanent residents.
"It indicates a problem. It indicates a loophole that we need to close," said Republican senator Ron Johnson, chairman of the Senate Homeland Security Committee.
In nearly all the cases, the girls were the younger person in the relationship. In 149 instances, the adult was older than 40, and in 28 cases the adult was over 50, the committee found.
In 2011, immigration officials approved a 14-year-old's petition for a 48-year-old spouse in Jamaica. A petition from a 71-year-old man was approved in 2013 for his 17-year-old wife in Guatemala.
There are no nationwide statistics on child marriage, but data from a few states suggests it is far from rare. State laws generally set 18 as the minimum age for marriage, yet every state allows exceptions.
Most states let 16 and 17-year-olds marry if they have parental consent, and several states - including New York, Virginia and Maryland - allow children under 16 to marry with court permission.
- Press Associaton