American Airlines is discontinuing flights to Venezuela as of last month. The airline was the last major U.S. carrier that flew to Venezuela, with daily flights to Caracas (CCS) and Maracaibo (MAR) from Miami (MIA).

The airline suspended the fights amid safety concerns, after the pilots’ union told its members to refuse to work daily flights to Venezuela. At the end of January, the United States issued a  “Do Not Travel” warning to U.S. citizens for Venezuela, which read, “Do not travel to Venezuela due to crime, civil unrest, poor health infrastructure, and arbitrary arrest and detention of U.S. citizens.”

The warning follows increased political unrest in the country, with President Nicolas Maduro jailing or barring opposition leaders from running against him in the last election. The United States removed its last diplomats out of Venezuela on Thursday.

“American will not operate to countries we don’t consider safe,” said spokesman Ross Feinstein.

United Airlines and Delta Air Lines stopped flying to Venezuela in 2017. Several other foreign carriers discontinued flights due to safety issues, and Venezuela’s government allegedly owed them billions of dollars. Last month, a crew for Air Europa was attacked at gunpoint in Caracas.