"The source of this war is in north Kurdistan [eastern Turkey] ... the guerrillas are not moving to the south [northern Iraq], on the contrary they are moving to ... places in the north," the PKK statement said.
"The guerrillas are positioning themselves against the attacks of the Turkish state."
"AKP [the ruling party] and CHP [opposition party] organisations in the region are among our targets", it said.
Hoda Abdel-Hamid, Al Jazeera's correspondent reporting from northern Iraq, said the Kurdish fighters defined their attacks as defensive action.
She said the rebel group was accusing the Turkish president, its military and some main opposition groups as forming a coalition against the Kurds.
Recep Tayyip Erdogan, the Turkish prime minister, earlier said he is ready to face international criticism should his country decide to attack suspected Kurdish rebel bases in northern Iraq.
Paying the price
Asked about world reaction to a possible incursion, Erdogan said: "After going down this route, its cost has already been calculated. Whatever the cost is, it will be met."
"Why is our government wasting time passing meaningless resolutions? Who cares what America thinks about another country's past?"
Tom Dougherty, Atlanta, USA
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"When we make a decision, we take into account Turkey's interests."
He also emphasised that Ankara had no territorial ambitions in Iraq.
After a recent increase of attacks by Kurdish fighters on Turkish troops, Erdogan's government has decided to seek approval from parliament next week for a major military operation to target members of the PKK, who use northern Iraq as a base to attack Turkish targets.
Erdogan said he wanted to secure parliament's approval now to avoid spending time later with the procedure if, and when, a cross-border operation was warranted.
Over the past few days the has sought to calm tensions with Turkey, after a vote on Wednesday in which the US House of Representatives foreign affairs committee branded the killings of Armenians by Ottoman Turks during World War One as genocide - a charge Turkey has firmly denied.
The US has also urged Ankara not to take unilateral action against the PKK.
The European Union, which Turkey wants to join, have also cautioned against such moves.
Meanwhile, analysts predict that an operation is more likely after the US congressional committee's decision.
The PKK is considered a terrorist group by Turkey, the US and the EU.
More than 37,000 people have been killed since the group began fighting for a homeland in 1984.
Turkey and Iraq signed an accord last month to combat the PKK, but failed to agree on a clause allowing Turkish troops to engage in "hot pursuit" against rebels fleeing into Iraqi territory, as they did regularly in the 1990s.
Ankara claims the PKK has used bases in northern Iraq to launch a renewed offensive inside Turkey that killed 15 soldiers last week.