Washington DC - Michael Banks, the US Border Patrol chief, resigned on Thursday, the latest senior immigration official to leave the Trump administration.
"We thank US Border Patrol Chief Michael Banks for his decades of service to this country," Customs and Border Protection Commissioner Rodney Scott said.
"During his time as chief, the border was transformed from chaos to the most secure border ever recorded," Scott said in a statement.
President Donald Trump campaigned for the White House on a pledge to prevent crossings of the US-Mexico border and has made an aggressive effort to expel millions of undocumented migrants.
Under Banks, the Border Patrol became involved in immigration operations away from the border, with agents carrying out controversial roundups of migrants in major cities across the country.
Trump replaced Homeland Security Secretary Kristi Noem in March amid continued outrage over the killing of two US citizens by immigration officials in Minnesota.
High-profile Border Patrol official Greg Bovino, meanwhile, was demoted following the fatal incidents in January and announced his retirement two months later.
Todd Lyons, the acting leader of the Immigration and Customs Enforcement agency, has announced plans to step down later this month.