Istanbul, Turkey (CNN) -- A Kurdish separatist movement has denied involvement in a bombing Thursday that killed nine people in a southeastern Turkish province, an explosion that drew swift condemnation and a vow to respond from Turkey's prime minister.
The Kurdistan Workers' Party, known as the PKK, said the cease-fire it declared last month, which is slated to expire September 20, "is still continuing."
"Our decision will definitely remain the same unless a new serious situation emerges," said a PKK statement published on Firat News Agency, a pro-Kurdish website.
The casualties -- which included four wounded -- occurred when a minibus drove over a landmine in a Hakkari province village. Provincial officials initially said 10 people had died, but amended that count.
In a news release sent to CNN, the PKK blamed the attack on what it called pro-government contra-guerrillas. Later, the PKK warned the Turkish government, saying, "The people of Hakkari is [sic] not alone."
The cease-fire had been declared for the Muslim month of Ramadan, which ended last week. It was issued in response to a call from Kurdish intellectuals and civil society organizations.
Speaking at an event in Istanbul, Prime Minister Recep Tayyip Erdogan said that "terrorism" is forcing Turkey to "pay a price."
"This will not be without a response," he said.
The volatile southeastern region is home to Turkey's ethnic Kurdish minority and the PKK, a one-time separatist group considered a terrorist organization by the Turkish government.
Turkey is reeling from a bloody summer of clashes with the PKK, the latest in a conflict that has simmered for more than 25 years. More than 30,000 people, mostly ethnic Kurds, have been killed.
Initially, the PKK fought to carve out a separate homeland for Turkey's ethnic Kurdish minority, which makes up roughly 20 percent of the Turkish population.
But in recent years, the rebels have said they are giving up their demands for an independent Kurdish state, and are instead fighting for more cultural freedoms.
CNN's Ivan Watson contributed to this story.