U.S. and Mexican officials are discussing an agreement that would ramp up Mexico’s immigration enforcement effort and allow the U.S. to deport asylum seekers as both sides work to clinch a deal that will avert tariffs on Mexican products, according to an administration official. It’s not clear if President Trump, who is traveling in Europe, or Mexican leaders would accept the terms of such an agreement. Delegations from both countries held staff-level talks in Washington on Thursday, one day after a meeting convened by Vice President Mike Pence did not result in a deal to avert sweeping tariffs on Mexican...