"Turkey will act with restraint but determination," said Ahmet Davutoglu, the Turkish foreign minister. "No one should try to put Turkey's capabilities to the test. No one should dare threaten Turkey's security."
Nato will discuss the incident in an emergency session tomorrow, after a request from Turkey under a rule that members can request a meeting if their security is threatened.
Recep Tayyip Erdogan, the prime minister, is expected to announce his government's reaction to the attack tomorrow. One Turkish expert said a military revenge attack would not be covered by international law.
Mr Davutoglu said all available data, including radio contacts and radar records, pointed to "an attack on a plane that did not display any hostile behaviour".
The Turkish foreign minister spoke after a series of meetings of government, military and intelligence officials in Ankara since the Phantom F-4 jet was brought down by Syrian anti-aircraft fire in the eastern Mediterranean on Friday.
"Our plane was hit in international airspace," Mr Davutoglu said in the first detailed statement about the incident.
"Syria's airspace is 12 miles. The plane was hit at 13 miles. Radar data show that it veered out of the pilot's control and began uncontrolled movements, and because it was out of control it dropped into the sea eight miles from the shore in Syrian waters after it was hit."
The search for the two missing pilots continued yesterday. The wreckage of the jet was reported to have been found at a depth of 1,300 metres.
Syria disputed the Turkish version. "What happened was an accident and not an assault as some like to say, because the plane was shot while it was in Syrian airspace and flew over Syrian territorial waters," the Syrian foreign ministry spokesman Jihad Makdissi said.
But Mr Davutoglu insisted available data and records, including records of Syrian radio contacts, suggested an unprovoked attack. He said the jet was unaccompanied, unarmed, clearly marked as a Turkish aircraft and on a routine training flight to test radar systems. Its mission had nothing to do with Syria and the insurgency there that has killed more than 15,000 people since the regime began a brutal repression of protests 16 months ago, he said.
"Unfortunately, Syria is engaged in disinformation," Mr Davutoglu said. He confirmed that the aircraft had briefly passed through Syrian airspace, but said that had been 15 minutes before it was shot down. There was no warning by the Syrians to the pilots, he said.
Oytun Orhan, an analyst at the Centre for Middle Eastern Strategic Studies, a think tank in Ankara, said he did not expect Nato to become involved because the downing of the jet had been an isolated incident.
Mr Davutoglu said he called more than a dozen leading international officials, including Ban Ki-moon, the UN secretary general, and the foreign ministers of the permanent UN Security Council members - the United States, Britain, France, Russia and China - to tell them about the destruction of the jet. Britain warned yesterday that the Syrian government "should not make the mistake of believing that it can act with impunity".
In Ankara, Mr Erdogan began a series of separate meetings yesterday with the leaders of opposition parties in parliament to brief them on the incident and present them with data about where the jet was shot down. Turkish media speculated the consultations could be in preparation for a vote by parliament on a mandate for the armed forces to intervene in Syria.
After a cabinet meeting today, Mr Erdogan is scheduled to address members of his ruling Justice and Development Party tomorrow, when he is expected to deliver Turkey's official response.
Yucel Acer, an expert on international law at 18th March University in north-western Turkey, said a military answer to the downing of the jet would not be legal unless there were repeated attacks by Syria.
"If there are no sustained attacks, an armed response is not legitimate," Prof Acer said yesterday. Turkey could take political or economic steps against Syria, or the two countries could try to resolve the issue by Syrian compensation payments if the two pilots have been killed, he said.