Watch the emotional reunion of a mother and 7-year-old son who were separated at U.S. border

A mother from Guatemala sobbed when she was reunited with her son in Baltimore Friday morning after being separated from him last month. Beata Mejia-Mejia and her son arrived at the U.S. border after a 2,300-mile, three-week journey by foot, seeking asylum from violence and domestic abuse. She was detained after they crossed into the U.S. near San Luis, Arizona, and said she had no idea where her son was for more than a month.

Asylum-seekers must go to an official port of entry to enter the U.S. legally, something Mejia-Mejia did not do. She and her son Darwin were taken to a detention center in Arizona. One day they called him by his name, she told CBS News' Weijia Jiang, and took him away.

A senior official told CBS News about 500 children have been reunited with their families since May. It's unclear how many of them are being detained with their families or remain in the U.S.

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Beata Mejia-Mejia and her son Darwin CBS News

Mejia-Mejia filed a federal lawsuit Tuesday against several government agencies and Trump administration officials, ordering them to release Darwin into her custody. On Thursday, the Justice Department agreed to release Darwin.

Now that they're back together, Mejia-Mejia said she's just wants to talk to him.  

The family's lawyers tell CBS News Darwin claims he received shots while at the detention facility. Now, he will receive a medical checkup, including a full blood test. Mejia-Mejia is now out on bond as she waits for a hearing on her asylum status set for August. Her lawsuit is still open.