The Turkish prime ministerial office says Turkey's military has struck targets inside Syria. This follows a mortar bomb believed fired from Syria that killed a women and four children in the Turkish town of Akcakale.
The statement from Prime Minister Tayyip Erdogan's office said Turkish artillery had fired "on points in Syria that were detected with radar, in line with the rules of engagement."
There were no immediate details of the Turkish strikes against Syria, nor was it clear who had fired the mortar into Turkish territory.
Earlier, Turkish Foreign Minster Ahmet Davutoglu had made telephone calls to the UN Secretary General Ban Ki-moon and the Syria crisis mediator Lakhdar Brahimi.
At the UN, Ban's spokesman, Martin Nersirky, said Ban called "on the Syrian government to respect fully the territorial integrity of its neighbors as well as to end the violence against the Syrian people" and to "keep open all channels of communication" to lessen "any tension that could build up as a result of the incident."
Clinton- situation "very dangerous"
US Secretary of State Hillary Clinton said Washington was "outraged that the Syrians have been shooting across the border." She described the situation as "very, very dangerous."
NATO Secretary General Anders Fogh Rasmussen said the alliance, of which Turkey is a member, was following developments "closely and with great concern."
In Akcakale residents infuriated by the spillover of violence from Syria's civil war took to the streets, directing their protest against local authorities.
Mortar struck town center
Leading local Red Cross official Ahmet Emin Meshurgul said Wednesday's mortar struck "right in the middle of the town," killing a mother and her four children, whom he knew personally.
Last weekend, Davutoglu had signaled that Turkey would take action if there was a repeat of a mortar strike which damaged homes and workplaces in Akcakale last Friday.
In April, Turkey officially reported an incident to the United Nations in which at least five people, including two Turkish officials, were wounded when cross-border gunfire hit a Syrian refugee camp in Kilis, further west along the frontier.
In June, Turkey beefed up its troop presence and air defences along its 900-kilometer (560 miles) border with Syria after a Turkish reconnaissance jet was downed.
Erdogan had long cultivated good relations with Syria's President Bashar Assad but became a harsh critic after Syria's revolt began last year. Turkey is now sheltering some 90,000 refugees from Syria in 13 camps.
ipj/rc (Reuters, AP, AFP)