Turkey has sent missile batteries, tanks and troops to the border with Syria as a "security corridor", almost a week after the Syrian downing of a Turkish military jet, media reports said on Thursday.
There was no official confirmation of the military moves, which came after Turkey branded its former ally a "clear and imminent threat" following Friday's attack over the Mediterranean.
About 30 military vehicles accompanied by a truck towing missile batteries left a base in the southeastern province of Hatay for the border, about 50 kilometres (30 miles) away, the Milliyet newspaper reported.
Footage aired on state-run TRT showed dozens of military vehicles loaded with army personnel, reportedly on the move for the volatile border, in a convoy that included low altitude air defence systems and anti-aircraft guns.
Taraf newspaper, citing unnamed sources, said the deployments represented the establishment of a "de facto security corridor" on Turkish soil.
The moves follow the downing of a Turkish Phantom F-4 jet by Syrian fire over the eastern Mediterranean on Friday in what Prime Minister Recep Tayyip Erdogan said was a "heinous attack" in international waters.
Erdogan vowed Tuesday that any hostile Syrian movement towards the border would be "treated as a military target," hinting at a harsher retaliation for any future border violations.
Turkey has described Syria as "a clear and imminent threat" but Erdogan said Wednesday that Ankara had no intention of attacking its neighbour.
Relations between the two countries have been left in tatters over the Damascus regime's brutal crackdown on an uprising that has now left about 15,800 people dead since March last year, according to activists.
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In a separate deployment, several trucks loaded with tanks were sent to the frontier in the province of Sanliurfa after a Kurdish rebel flag was hoisted in a Syrian village just across the border, provincial media said.
The flag, which reportedly belonged to a Syrian wing of the outlawed Kurdistan Workers Party (PKK) was taken down early Thursday, the Anatolia news agency said, citing local witnesses.
Turkish officials have frequently accused Syria of aiding the PKK after Ankara's ties with Damascus broke down, saying many recent attacks targeting Turkish security forces were carried out by rebels infiltrating from Syria.
Turkey's powerful army has not confirmed the deployments, but earlier it dismissed reports that it was "on alert" after the downing of the jet, whose two crew members are still missing.
Turkish media have interpreted the mass deployments both as a means to intimidate Kurdish rebels, whose activities have increased in recent months, and as a challenge to Syria, which shares a 910-kilometre border with Turkey.
"Wouldn't such moves inevitably cause Syria to put its own forces on alert and shift troops to the border while at the same time it has to deal with clashes inside?" Taraf columnist Almet Altan said in an article on Tuesday.
Erdogan was once a friend and ally of Syrian President Bashar al-Assad but relations have broken down since the revolt erupted in Syria last year, sending more than 33,000 refugees across the border into Turkey.
Turkey closed its embassy in Damascus earlier this year after kicking out the Syrian ambassador to Ankara.
Meanwhile, the Turkish military said it had found some materials from the downed jet and some of the crew's belongings but has not found the wreckage nor the two missing men.
The search involves five military boats and four helicopters and the army said it has also mobilised a hydrographic survey ship and will be using another vessel to search at a depth of about 1,260 metres (over 4,000 feet).