An Associated Press video journalist said Turkish artillery fired toward Syria minutes after a Syrian shell landed on Turkish territory.
The Syrian shell landed some 200 meters (200 yards) inside Turkey, near the border town of Akçakale. A short time later, at least six mortars could be heard fired from Turkey. It was the fifth day in a row that Turkey returned fire.
Abdulhakim Ayhan, the mayor of Akçakale, confirmed that Turkish artillery immediately returned fire.
There were no immediate reports of casualties in the latest incident.
In the latest blow to the already strained ties between the two neighbors, Syria fired mortar shells into a residential district of the southeastern Turkish town of Akçakale on Wednesday, killing a woman and four children from the same family and wounding at least 13 people. In response, Turkey attacked targets inside Syria. The incident represents the most serious cross-border escalation of the 18-month uprising in Syria.