Six soldiers were killed and 15 wounded in the ensuing clashes. One member of the PKK was shot dead.
"We will pursue our struggle against terrorism with determination," said Turkish Prime Minister Recep Tayyip Erdogan. "We will not take even one small step back," he added.
An operation to capture the militants was underway on Tuesday, although it was not clear whether they had come from northern Iraq, a refuge of the PKK.
"This latest attack is really part of a string of similiar attacks, mainly targeting these remote border posts," says Istanbul correspondent Nicole Pope.
Last week Erdogan announced new measures to post specially-trained soldiers along the Iraqi border to fight the PKK and stop them from entering Turkey.
"There has been quite a lot of debate in Turkey about whether it is really necessary in this day and age for soldiers - especially young conscripts who are very inexperienced - to be deployed to these remote areas in the mountains, which are really pretty inaccessible and not easy to defend," Pope added.
The PKK dramatically stepped up its 26-year separatist campaign after its jailed leader Abdullah Ocalan said through his lawyers in late May that he was abandoning efforts to seek dialogue with Ankara.
Last month, radical Kurdish militants claimed responsibility for a remote-control roadside bomb that hit a bus carrying army personnel in Istanbul, killing five soldiers and the teenage daughter of an officer.