The Americans were identified by Christallin as members of an Idaho-based Baptist group called New Life Children's Refuge.
He said two pastors were also involved, one in Haiti and one in Atlanta, Georgia.
Their plan was to take around 100 children by bus to a rented hotel at a beach resort in the Dominican Republic, where they planned to establish an orphanage.
Mario Andresol, a Haitian police chief, said the Americans were awaiting a hearing before a judge on Monday in Port-au-Prince, the Haitian capital, and the children had been transferred to a facility north of the city, in Croix de Bouquets.
Laura Silsby, the group's leader, said on Sunday: "In this chaos the government is in right now, we were just trying to do the right thing."
She told The Associated Press news agency that the group only had the best of intentions and paid no money for the children, whom she said they obtained from Jean Sanbil, a Haitian pastor at the Sharing Jesus Ministries.
When asked if she thought it was naive to cross the border without adoption papers at a time when Haitians are so concerned about child trafficking, Silsby said: "By no means are we any part of that. That's exactly what we are trying to combat."
The US embassy in Port-au-Prince said that ten US citizens were being held in Haiti for "alleged violations of Haitian laws related to immigration".
"American diplomats have visited the detained Americans and are in communication with Haitian authorities," the embassy said in a statement.
"As always, US embassy officials will take all appropriate steps to ensure the wellbeing of US citizens detained abroad."
Amanda Weisbaum, from the non-profit organisation, Save the Children, told Al Jazeera that taking children out of their home country is not in their best interests.
"Experience has shown it is better to keep the children in the place, and with the people, they know," she said.
"We trying to make sure that all these children still have parents or families within the area and that hasn't been ascertained yet.
"The Haitian government was quite right to halt these people at the border if they felt they didn't have the right paperwork."
Haitian officials have voiced fears that child traffickers will take advantage of the chaos after Haiti's 7.0 magnitude January 12 earthquake to leave the country with children in illegal adoption schemes.
There is also concern that legitimate adoption agencies may rush to take earthquake orphans out of the country before proper checks have been conducted to confirm that their parents have died.
The United States has urged citizens moved by Haiti's earthquake to show patience in adopting children, and Haiti said its prime minister will have to sign off on every
minor's departure abroad for the time being.