General Yasar Buyukanit, the Turkish army's new chief of staff, said on Monday there would be no change in the army's position and called on the PKK to lay down its arms and surrender.
In his speech, which was broadcast live on Turkish television stations, he said: "The Turkish armed forces have said that they will fight on until not a single armed terrorist is left. There has been no change in that position nor will there ever be.
"The only way out for the terrorist organisation is to lay down arms unconditionally and to give themselves up to Turkish justice system."
"There is mention of a ceasefire as though there were two countries at war.
His comments came hours before Recep Tayyip Erdogan, the prime minister, and George Bush, the US president, were expected to discuss Turkey's conflict with its Kurds during a meeting in Washington.
Turkey wants the US to crack down on the fighters who operate partly out of bases in northern Iraq.
The PKK is fighting for an independent Kurdish state, but has said that they would be content with winning greater recognition of Kurdish cultural rights - such as making Kurdish an official language in Turkey.
Three days before the PKK announced a ceasefire on Saturday, Abdullah Ocalan, the group's imprisoned leader, issued a statement calling on his fighters to cease their attacks.
Speaking from northern Iraq on Saturday, Murat Karayilan, one of the most senior PKK commanders, said that the group would lay down its arms only if the Turkish state had a democratic solution to the Kurdish issue.
Murad Karayilan, a PKK leader, has called for a ceasefire
Zubeyir Aydar, head of Kongra-gel which claims to be the political wing of the PKK but is considered a terrorist group by Ankara and the EU, said at a meeting in Metz, France, that the ceasefire was declared to give a chance for a political solution, the pro-Kurdish Firat news agency reported on Monday.
"This opportunity must be evaluated carefully by everyone so that there is no more suffering," Aydar was quoted as saying.
Turkey does not recognise the 15 million Turkish Kurds as an ethnic minority, and so does not extend them minority rights, such as being educated in their own language.
The European Union has said that Turkey must extend greater rights to Kurds and other minorities in order to join the 25-nation bloc.
The conflict has claimed the lives of 37,000 people since the PKK took up arms in 1984.