Turkey's cabinet has wrapped up a seven-hour meeting over the downing of a Turkish jet by Syrian forces, just hours before NATO was due to meet to discuss the incident.
After the meeting ended on Monday night, Bulent Arinc, the deputy prime minister, said that "all options were on the table" for Turkey's response.
"Syria shot down our unarmed jet in a cold-blooded and hostile way in international airspace," he said. "International law is on our side."
Arinc also said that a second Turkish plane came under fire while searching for the jet that was shot down. But he stressed that Ankara "does not intend to make war with anybody".
"One of our CASA planes took off with a rescue team. Unfortunately, shots from the ground targeted our plane. Our foreign ministry and our military command notified Syrian authorities and this harassment ceased immediately," Arinc said.
The Syrian government has disputed Turkey's claim that the downed jet was in international airspace.
Jihad Makdissi, foreign ministry spokesman, said earlier on Monday that "the Turkish warplane violated Syrian airspace, and in turn Syrian air defences fired back and the plane crashed inside Syrian territorial waters".
"What happened is a gross violation of Syrian sovereignty," he said.
"If the goal of the [NATO] meeting is to calm the situation and promote stability, we wish it success ... but if the goal of the meeting is aggression, we say that Syrian airspace, territory and waters are sacred for the Syrian army, just as Turkish airspace, territory and waters are sacred for the Turkish army."
Turkey has called an extraordinary NATO meeting for Tuesday to discuss the incident, which came at a time of heightened tensions between the two onetime allies.
Earlier, Turkey's state-run news agency said 33 more members of the Syrian military had defected to Turkey.
The Anadolu agency said on Monday that the group, which included a general and two colonels, crossed into Turkey overnight and that they were being hosted at a refugee camp near the border.
The defection brought to 13 the number of generals seeking refuge in Turkey since the revolt against Syrian President Bashar al-Assad's regime erupted 16 months ago.
Thousands of soldiers have abandoned the army, but most are low-level conscripts. The Free Syrian Army, the loosely-linked group of rebel forces, is made up largely of defectors.
In another development, the European Union's foreign policy council met in Luxembourg on Monday to discuss, among other things, the crisis in Syria.
The EU is planning to add another Syrian official and six firms and government institutions to a sanctions list which already includes more than 120 individuals and nearly 50 entities, a spokesman said.
The asset freeze and travel ban will be the 16th round of restrictive EU measures imposed on Assad's government. No details were immediately available on the identities of those targeted.
The sanctions also include a specific ban on insuring items embargoed for delivery to Syria, including arms shipments.
In-depth coverage of escalating violence across Syria
Meanwhile, on the ground, Syrian troops pounded the central city of Homs on Monday amid warnings from the rebel Free Syrian Army (FSA) of an impending "massacre" there.
The Syrian National Council (SNC), the main political opposition bloc, issued a distress plea from residents, urging international help "before it is too late."
Activists reported shelling of the neighbourhoods of Jouret al-Shayyah and al-Hamidiyeh using rockets and artillery.
The FSA said "Arab and Islamic countries, friendly nations and concerned international organisations" bore responsibility for what happens.
"The brave city of Homs faces the strongest and most violent bombardment of rockets, artillery and tanks," its Supreme Military Council said in a statement.
"The regime is sending reinforcements estimated at 100 tanks in the direction of Homs... which clearly demonstrates its intention to commit the greatest massacre in history."