As Fei Zheng is being held at the Orange County Correctional Facility, his son, Yuanxin, is in the custody of the Office of Refugee Resettlement.

Yuanxin Zheng.Courtesy of Zheng family

More than 200 people rallied Sunday in support of a Chinese father who is in immigration detention while his 6-year-old son is in being held by the Office of Refugee Resettlement following a routine immigration appointment in New York City.

Fei Zheng and his son, Yuanxin, showed up to the offices of Immigration and Customs Enforcement in New York City on Nov. 26 for a routine check-in, according to Jennie Spector, a community activist who coordinated two volunteers to accompany Zheng and Yuanxin to the appointment. The volunteers waited for Zheng and his son outside the ICE offices, since they`re not allowed inside check-ins.

"They never heard from him," Spector told NBC News on Monday. "After a number of hours, we kind of assumed that they had been arrested."

Fei Zheng and his son, Yuanxin.Courtesy of Zheng family

Zheng was taken to the Orange County Correctional Facility, where he remained in immigration custody as of Monday, and his son was transferred to the custody of the Office of Refugee Resettlement, which holds unaccompanied immigrant children, according to the Department of Homeland Security.

A child taken into ORR custody is placed with an ORR-approved guardian, similar to a foster family, or taken to an ORR facility. It is unclear exactly where ORR is holding the boy.

Spector, who receives calls from Zheng while he is in detention, said the father was able to briefly speak with his son over the weekend. That was his first time hearing his son`s voice since they were separated on Thanksgiving eve, Spector said.

"He was able to be put in touch with his son, but he doesn`t know exactly where he is or what kind of place he is living in," Spector said. "No one has confirmed that to him."

DHS Assistant Secretary Tricia McLaughlin told NBC News in an email that "ICE does not separate families," but places minors and adults in custody as "consistent with past administrations immigration enforcement."

According to McLaughlin, Zheng and Yuanxin are Chinese nationals who are living in the United States without authorization and "were given a lawful order of removal as a family unit."

Mike Gao, an attorney for Zheng, previously told The New York Times that his client had refused to board an ICE flight to China in September because he feared government retribution there. Gao did not respond to a request for comment from NBC News.

"Mr. Zheng refused to board the plane and was acting so disruptive and aggressive that he endangered the child`s wellbeing," McLaughlin said, adding that the father "had the right and the ability to depart the country as a family and willfully choose to not comply."

"To be clear, refusing a judge`s deportation order is a crime. As a result, the child was placed with ORR Custody," McLaughlin said.

Over 200 people gathered Sunday for an anti-ICE protest in Astoria, Queens.Courtesy Indivisible Western Queens

Over 200 people, many of them members of Yuanxin`s school community, attended Sunday`s protest, according to Devora Fein, a leader of the western Queens chapter of Indivisible, a group that opposes the Trump administration`s immigration policies and which organized the rally.

They gathered at a playground in Astoria, where children and adults were seen holding signs that read: "Kids Aren`t Pawns" and "Kids Belong In School Not In Detention."

"They wanted a place to come together to voice their outrage, to be among others who are feeling the same and want to send this message to Trump and ICE that this is unacceptable," Fein told NBC News on Monday. "We cannot pull children into this horrible game."

New York City Comptroller Brad Lander at the rally Sunday.Courtesy Indivisible Western Queens

Community advocates reached out to Democratic Reps. Nydia Velazquez and Grace Meng, both of New York, as well as New York City Council Member Julie Won to request help locating Yuanxin and push federal authorities to reunite the boy with his father.

"We are pushing for answers and doing everything we can to support this family during this incredibly difficult time. Our offices have been in touch with the attorneys for Fei and Yuanxin and with the appropriate city and federal agencies," Velazquez, Meng and Won said in a joint statement Friday. "At this time, though there are legal limits on what can be shared publicly."

The Democratic lawmakers added: "Immigration proceedings should not end with a family being torn apart and a 6-year-old child separated from his parent. Families must never be used as leverage to force deportations. Situations like this traumatize immigrant communities and sow distrust of the government."

A demonstrator holds up a sign at Sunday`s rally.Courtesy Indivisible Western Queens

According to the local news outlet The City, which first reported on the case, Zheng first attempted to cross the southern border with Yuanxin in April to seek asylum in the United States. They spent several weeks inside a family ICE detention center and were released on parole in early summer. They were arrested again at an August ICE check-in and returned to Dilley Immigration Processing Center, the family detention center where the two had previously been held.

Online records of the Executive Office for Immigration Review show Zheng and Yuanxin had an immigration court hearing on Sept. 8 while they remained detained. According to The City, a judge administratively closed their asylum case during that hearing, often considered a sign that DHS is not actively seeking the person`s deportation.

The father and son were then released on Oct. 24, Spector told NBC News. "They were given parole for a year, and then just a month into that they were arrested again," she said. The family had settled in New York City and Yuanxin had just started first grade at a public school in Astoria, Queens.

One of Yuanxin`s teachers showed up to Sunday`s rally and delivered an impromptu message, Fein said. The teacher said the 6-year-old boy loves making puppets and playing with them and described him as "incredibly good at math for a first grader."

"He has amazing handwriting both in English and Mandarin. He loves to sing and dance to our ‘Good Morning` song during our morning meetings. He is great at making friends and he is an important part of our classroom community," the woman said as she tearfully choked up. "Our class feels his absence every single day."