Story highlights CBP has long struggled to even keep up with attrition

Trump has requested 5,000 more agents be hired

Washington (CNN) Optimistic internal estimates say that it could still take five to 10 years for Customs and Border Protection to hire all the additional agents President Donald Trump has ordered, even if the agency gets a wish list of requests to make hiring easier, according to documents obtained by CNN.

CBP has long struggled to even keep up with attrition in its ranks, and was staffed below currently targeted levels even before the President's January executive orders called for 5,000 more agents.

CBP's acting commissioner spelled out a series of steps the agency would need, either from other agencies, its parent DHS or Congress, in order to hire more agents in a memo for the deputy secretary last month, according to a copy obtained by CNN.

But even those measures would only help so much, the memo makes clear.

The hurdles are just the latest practical difficulty faced by Trump's attempts to substantially increase immigration enforcement in the US. His moves to vastly increase the number of undocumented immigrants detained and deported have rankled Democrats and spread fear in immigrant communities. In addition to his long-promised border wall, Trump has ordered a substantial increase in personnel, including the CBP surge.

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