In March 1987, a decision of the Greek government to nationalize the consortium of companies that was drilling oil off Thasos, and planned exploratory oil drilling 17 kilometres (11 mi) east of the island of Thasos, such as the impression by Turkey that Greece was planning new researches for oil, provoked tension between the two countries.
The crisis escalated, armed forces of both countries were on alert, and each side said they would use force if obstructed by the other.[2] The incident nearly started a war between Greece and Turkey.[4]
Greek prime minister Andreas Papandreou gave the orders to sink the ship if it was found in Greek waters. 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. The Greek government gave orders for the suspension of operation of the base of NATO in Nea Makri, while the Greek forces and Navy were alarmed.
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.[2]