CHANIA, Greece (AP) — Protesters gathered on the Greek island of Crete late Tuesday following the arrival of a U.S. aircraft carrier that is part of a major buildup of American forces in the Middle East.

The USS Gerald R. Ford, the world’s largest aircraft carrier, docked Monday at the American naval base at Souda Bay on Crete, amid warnings by U.S. President Donald Trump of possible military action against Iran.

The peaceful rally, backed by the Greek Communist Party, was held in the nearby port city of Chania. Protesters held up individual placards with letters spelling out “Killers" in English.

Regional tensions have spiked again, largely over the future of Iran’s nuclear program.