Turkey learned that Greece was starting to drill for oil in the Aegean Sea in the vicinity of Thasos, a Greek territory.

Greece claimed ownership of mineral rights in the continental shelf extending from beneath all its islands in the Aegean.

Turkish Prime Minister Turgut Özal said that "If Greece interferes with our vessel in any way, and this is what Papandreou is saying, we will act in the same way against him", "As a result, it could be cause for war," but he also added that "We are waiting for the first move from them.

"[2] The Greek foreign minister Karolos Papoulias was sent to Bulgaria (then a member of the Warsaw Pact) for discussions.

Britain's Lord Carrington, the secretary general of NATO, urged Greece and Turkey to avoid the use of force and offered to act as a mediator.