Bill de Blasio, a Democrat, is the 109th Mayor of New York City. The views expressed in this commentary are his own.

(CNN) There is a terrified 9-year-old boy in New York City right now. He and his mother fled Honduras to come to the United States' southern border. They had hoped our country would protect them from gang violence. Instead, the Trump administration yanked them apart, detained the child's mother and sent him to a federally-contracted facility in New York.

There are many like him in New York City today thanks to President Donald Trump's zero-tolerance policy with respect to people crossing our borders. By the administration's own admission, they are taking children from their parents -- and likely doing those innocent children lasting psychological harm -- in an effort at deterrence that is as heartless as it is cynical.

Bill de Blasio

In many cases, the victims of this cruelty are fleeing hopeless and dangerous situations in their countries. I might add, some are actually fleeing the very MS-13 gang the President himself repeatedly cites as a threat to the safety of Americans. Why else would mothers who are still cradling breastfeeding babies in their arms make thousand-mile journeys across Central America? They are convinced they have no choice.

These children must be reunited with their families immediately, and all of us must hold the perpetrators of this shocking policy accountable. Trump can point his finger wherever he wants, including, most recently, at Democratic lawmakers, but the facts are clear. Families are being ripped apart because of a policy his administration put in place. No one forced Trump's hand. He doesn't need Congress. He could stop this right now.

The President's Attorney General Jeff Sessions even quoted the Bible to justify these horrors. "I would cite you to the Apostle Paul and his clear and wise command in Romans 13, to obey the laws of the government because God has ordained the government for his purposes," he said.

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