Why Frontex won't leave Greece, like it left Hungary Frontex's Operation Poseidon in Greece is among its largest (Photo: Frontex) Brussels, Today, 07:06 Earlier this year, the EU law-enforcement agency Frontex pulled out of Hungary, over violations committed against asylum seekers. Frontex had, however, sat on the issue for five years, despite the evidence. Read and decide Get instant access to all articles — and 20 years of archives. 14-day free trial. Choose your plan Our exclusive news stories and investigations. Influential. Investigative. Independent. Why join? Already a member? The Warsaw-based agency finally left after EU judges in December told Hungary to stop pushing asylum seekers back into Serbia.