Turkey has hit Syrian military positions for the sixth day in a row after a shell fired by the neighbouring country landed across the border.
Turkey retaliated in kind after the Syrian shell landed in Altinozu district, in southeastern Hatay province, at around 1200 GMT, according to an anonymous official.
"Turkish military retaliates immediately after every single Syrian shell," said the official. "We have anti-aircraft batteries pounding Syrian targets."
Earlier, Hatay's governor said a total of six Syrian shells had hit the Turkish side of the border on Monday, without any casualties.
But it was not immediately clear if the governor's figures included the latest shelling.
"All of them landed in rural areas," said Celalettin Lekesiz, in remarks carried by Anatolia, the state news agency.
The latest incident came on the sixth day of sporadic fire exchange between Turkey and Syria, which was inflamed after Wednesday's deadly shelling fired by Damascus.
Syrian shells hit Akcakale border town in Sanliurfa Wednesday, killing five nationals. Since then, the Turkish military has responded in kind whenever Syrian fire has breached its territory.
Wednesday's incident was the most serious between Damascus and Ankara since Syrian anti-aircraft fire brought down a Turkish fighter jet in June, and renewed fears of a broader conflict.
The Turkish parliament on Thursday gave the government the green light to use military force against Syria if necessary.
The UN Security Council on Thursday strongly condemned cross-border attacks by Syria and called for restraint between the two neighbours.
Earlier Ban Ki-moon, the UN Secretary General, warned of a "dangerous" fallout from the spiralling violence.
"The escalation of the conflict along the Syrian-Turkish border and the impact of the crisis on Lebanon are extremely dangerous," Mr Ban said at the opening of the World Forum for Democracy in Strasbourg, France.
The UN chief also raised concerns about arms supplies to both President Bashar al-Assad's regime and rebel forces.
"I am deeply concerned by the continued flow of arms to both the Syrian government and opposition forces. I urge again those countries providing arms to stop doing so."
"Militarisation only aggravates the situation," he said. "I am calling on all concerned to abandon the use of violence, and move toward a political solution. That is the only way out of the crisis."
Inside Syria, regime artillery before dawn on Monday shelled a string of rebel strongholds, the Syrian Observatory for Human Rights said, adding that insurgents for their part attacked several army checkpoints.
The watchdog gave an initial toll of 61 people killed on Monday, saying most of the deaths occurred when the army launched intensive pre-dawn assaults on the town of Karak al-Sharqi in the southern province of Daraa and on pockets of rebel resistance in Aleppo, Syria's commercial capital.