Oinousses, some incidents have also repeatedly been reported involving major and undisputed islands such as Rhodes, Lesbos, Chios or Leros. Flying over the territory of a country is considered a serious violation of its sovereignty and one of the most provocative acts by Turkey, directly challenging Greek territorial sovereignty. In 2020, Turkish fighter aircraft also begun overflights above the Greek mainland, on Evros. A regional Foreign Minister conference held on 11 May 2020 with the participation of Cyprus, Egypt, France, Greece and the United Arab Emirates, concluded with a joint declaration condemning Turkey for its practice of conducting armed overflights above the inhabited Greek islands. In 2022, Turkish bomber aircraft approached the major Greek city of Alexandroupolis on Evros, within 2.5 miles. The jets reportedly flew near the US base located in the city's port. This move is considered to be unprecedented, prompting protests from both the Greek authorities and the European Union, as well as USA's disapproval, with the Head of Turkey's Permanent Representation to the European Union Mehmet Bozay being summoned at Brussels by the Secretary General of the European Union External Action Service, Stefano Sannino. Turkish incidents with Frontex In September 2009, a Turkish military radar issued a warning to a Latvian helicopter patrolling in the eastern Aegean—part of the EU's Frontex programme to combat illegal immigration—to leave the area. The Turkish General Staff reported that the Latvian Frontex aircraft had violated Turkish airspace west of Didim. According to a Hellenic Air Force announcement, the incident occurred as the Frontex helicopter—identified as an Italian-made Agusta A109—was patrolling in Greek air space near the small isle of Farmakonisi, which lies on a favorite route used by migrant smugglers ferrying mostly illegal migrants into Greece and the EU from the opposite Turkish coastline. Frontex officials stated that they simply ignored the Turkish warnings as they did not recognise their being in Turkish airspace and continued their duties. Another incident took place in October 2009 in the aerial area above the eastern Aegean sea, off the island of Lesbos. On 20 November 2009, the Turkish General Staff issued a press note alleging that an Estonian Border Guard aircraft Let L-410 UVP taking off from Kos on a Frontex mission had violated Turkish airspace west of Söke. Strategies of conflict resolution The decades since the 1970s have seen a repeated heightening and abating of political and military tensions over the Aegean.