Two children are missing, according to an AMBER alert, and the San Antonio Police Department said they are believed to be in grave or immediate danger.

Fidely Alvarez Mauricio, 10, and Neidy Alvarez Mauricio, 13, were last seen at 1 a.m. Saturday in the 1200 block of Logwood Avenue on the South Side, police said.

They were last seen with Pedro Alvarez-Castillo, 48, who police said is wanted for possibly abducting the children.