Turkish special forces entered northern Syria, ground incursion yet to begin: sources

ANKARA (Reuters) - A group of Turkish special forces units have crossed into northern Syria but the ground incursion has not yet begun and work to open a passage way is continuing, a senior Turkish official and military sources said on Wednesday. Turkish warplanes and U.S.-led coalition aircraft have carried out four strikes on Islamic State targets, Turkish military sources said, as part of a joint operation to wipe out Islamic State from the Syrian border town of Jarablus. A total of 63 targets have been fired at 224 times with Turkish artillery and shelling. "The aim of the operation is to ensure border security and Syria's territorial integrity while supporting the U.S.-led coalition against Islamic State," one of the military sources said. (Reporting by Orhan Coskun; Writing by Humeyra Pamuk; editing by Patrick Markey)