Update at 6:30 a.m. Wednesday: Iranian cancer researcher Dr. Sayed Mohsen Dehnavi and his family were put on a flight back to Iran Tuesday night, per U.S. Customs and Border Protection and Boston Children's Hospital.

Original story:

An Iranian researcher coming to work at Boston Children's Hospital as a visiting scholar has been denied entry to the United States.

Sayed Mohsen Dehnavi, his wife and three children -- the youngest of whom is 7 months old — have been detained at Logan Airport since Monday afternoon according to Prasant Desai, an immigration attorney working on behalf of Boston Children's Hospital.

Stephanie Malin, a spokeswoman for U.S. Customs and Border Protection (CBP), said Tuesday afternoon that the family's detention was not related to President Trump's executive order blocking new visas for residents of six predominantly Muslim countries, which was largely reinstated by the Supreme Court last month.

Malin said Dehnavi and his family were "deemed inadmissible to the U.S. based on information discovered during the CBP inspection" and "as is customary with individuals denied entry to the U.S., they will depart on the next scheduled flight."

She noted that visa applicants "bear the burden of proof to establish that they are clearly eligible to enter the United States" and can be denied entry for a number of reasons, including health-related grounds, criminality and security reasons.

Desai says border officials at Logan have not provided him with any details about why Dehnavi and his family have been denied entry and have not allowed him to speak to Dehnavi.

Border agents have broad authority to decide who is allowed into the country, and travelers seeking entry into the U.S. are not legally entitled to an attorney unless they have become the focus of a criminal investigation.

"[Dehnavi] is a researcher, he has a relationship with a laboratory at Children's Hospital, and from what I know, what I've been told, he has many contributions to make," said Desai, who spent most of Tuesday morning at Logan.

Desai says it appears that Dehnavi's J-1 visa, which was issued in May, is in order. He says even if the family's detainment isn't related to the travel ban, he still thinks it's "an indication that folks from some countries will need to be even better prepared than normal."

Susan Church, the former chair of the American Immigration Lawyers Association of New England, says the detention of Dehnavi and his family sends the wrong message to the international community.

"This government is very much enforcing the rules in overzealous and unfair manner," Church said. "We're continuing to send a message to the world that we're not friendly to immigrants."

With reporting from the WBUR Newsroom

Correction: An earlier version of this story incorrectly identified Susan Church as chair of the American Immigration Lawyers Association of New England. Her tenure as chair recently ended. We regret the error.