No, these detention centers are not 'concentration camps'. Not in the accepted context of the words.
For starter...You can be detained without being charged because you broke a law. A conviction came only after a charge and a trial. But the initial detention is legitimate for many reasons, from for your own safety to for the victim's safety to preventing your escape. So being detained by itself is not immoral.
Next...Every country have the right and duty to control access to its territory. If a country observes borders, then that right and duty are inherent. From that perspective, every country have the same right and duty to insist that entry in specific manners be observed. If neighbors are friendly enough then they have the right to ignore borders if they chose, but non-observance in specific circumstances does not negate those right and duty.
Next...These detention centers are for returning illegal immigrants to their original countries, not for killing them. Some maybe allowed entry, but overall, the US want to return them to their original countries.
So to say that these detention centers are 'concentration camps' in the sense of the Nazis did and what China is doing to the Muslims is morally and legally absurd.