Mexican immigration officers will check travel documents for travelers crossing the U.S-Mexico border, part of a new pilot program launched at the San Ysidro Port of Entry this week. Some immigration advocates have already started voicing concerns. U.S. border authorities previously checked San Diego-bound travelers but now Mexican and U.S. officers will do the checks. MORE: https://www.cbs8.com/article/news/local/officers-in-mexico-to-assist-with-document-checks-for-travelers/509-7d4b8efb-e8c6-4828-87dc-89cb3872fb95