Apart from what Dan says, children are required to have permission to travel internationally from both parents. If you and your partner travel together with the children, nothing else is needed. But if only you go, occupy a notarized letter from the mother of the children giving you permission to travel and return from Colombia. Enter dates
If you want to return to the US, you need to have some document that allows you to enter, such as a US passport, permanent residence card, or visa.
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