"We are heartbroken by the violence that was targeted at our city today, and by the allegations being made against a member of our family," the family said in a statement read by Albert Fox Cahn, the legal director of the Council of American-Islamic Relations-New York.
"But we are also outraged by the behavior of the law enforcement officials who have held children as small as 4 years old out in the cold and who pulled a teenager out of high school classes to interrogate him without a lawyer, without his parents," the family added. "These are not the sorts of actions we expect from our justice system, and we have every confidence that our justice system will find the truth behind this attack, and that we will, in the end, be able to learn what occurred today."
It is not clear if the statement is referring to children who are part of the family, or other non-family members.
Akayed Ullah is in custody after the attempted terrorist attack rocked the busy New York Port Authority subway station.
The explosion occurred in a heavily-trafficked underground walkway in the middle of the morning rush hour.
President Donald Trump cited the attack to push his immigration initiatives aimed at tightening restrictions for those seeking U.S. entry, particularly individuals from Muslim-majority countries.
"America must fix its lax immigration system, which allows far too many dangerous, inadequately vetted people to access our country," he said in a statement issued hours after the attack.
"My Executive action to restrict the entry of certain nationals from eight countries, which the Supreme Court recently allowed to take effect, is just one step forward in securing our immigration system."
Ullah is reportedly from Bangladesh – a country not on Trump’s travel ban, but the president has sought a separate end to so-called "chain migration", or U.S. entry based on extended familial relations.
Saying Ullah used the program to enter the U.S., Trump called it "incompatible with national security" and urged lawmakers to bring it to an end.
New York Police Commissioner James O'Neill said the suspect sustained burns and wounds to his body and hands during the attack and is being treated at an area hospital.
O'Neill said the suspect made statements but declined to elaborate on the nature of the remarks or if he claimed the attack was carried out for the Daesh terror group.
But preliminary information indicates the suspect has been living in the U.S. for seven years, according to former New York Police Commissioner Bill Bratton, who told MSNBC that Ullah claimed the attack for Daesh.
An unnamed law enforcement source told CNN that Ullah said he carried out the attack because of recent Israeli actions in the Gaza Strip. Ullah allegedly told investigators he chose to detonate the bomb inside the walkway because he noticed a Christmas advertisement on the wall and was inspired by past Daesh-motivated Christmas attacks, according to NBC.
Law enforcement sources told NBC it does not appear Ullah has direct ties to the terror group.
Authorities said only three victims sustained non-life-threatening injuries and were able to transport themselves to local hospitals.
“This is the most resilient place on Earth,” declared New York Mayor Bill de Blasio. “The terrorists will not win. We’re going to keep being New Yorkers.”
The explosive device used was attached to Ullah's body using Velcro and zip ties and was based on a pipe bomb, according to police. O'Neill separately described the bomb as an "improvised low-tech device".
It included matches, a nine-volt battery and a Christmas light, according to The Associated Press. It did not have enough explosive material in it to make pipe pieces into potentially fatal shrapnel.
Police activity is heightened throughout the city, although officials emphasized there are no other specific credible threats to New York at this time.
New Jersey Governor Chris Christie said his state's law enforcement officials are coordinating with their federal and New York counterparts, and he directed New Jersey police to step up security at major transportation hubs.
The attack Monday came just weeks after a deadly rampage in lower Manhattan in which a suspect ran over pedestrians and cyclists on a bike path, later claiming the attack for Daesh. Authorities identified him as Sayfullo Saipov, an immigrant from Uzbekistan who came to the U.S. on a diversity visa.
"We have now seen two terrorist attacks in New York City in less than two months that were carried out by people who came here as the result of our failed immigration policies that do not serve the national interest—the diversity lottery and chain migration," Attorney General Jeff Sessions remarked in a statement.
"It is a failure of logic and sound policy not to adopt a merit-based immigration system," he added.