Six people, including at least four civilians, were killed Thursday in ongoing clashes between Turkey's armed forces and militants in the mainly Kurdish southeast, security sources and officials said. Smoke rose above the town of Cizre near the Syrian border after Kurdistan Workers Party (PKK) rebels armed with rocket launchers attacked a military base, witnesses and security sources said. Days of street fighting between soldiers and militia fighters raged on overnight in the town of Yuksekova, near the border with Iraq and Iran, despite a curfew there, officials added. "There are people with critical injuries who are being treated in homes. Security forces have shelled a neighborhood, and hit residential buildings," said Abdullah Zeydan, a lawmaker in the pro-Kurdish Peoples' Democratic Party (HDP). A 2-1/2-year-old cease-fire between Turkey and Kurdish militants collapsed in July. An estimated 800 PKK fighters, more than 60 soldiers and police officers and 12 civilians have been killed, according to government sources and Turkish media. The fighting in Cizre killed three people and wounded seven, including a 7-year-old child, security sources said. Gunfire rang out for hours after the initial attack, Reuters video footage showed. Three other people were killed in Yuksekova, a local government official said on condition of anonymity. One of them was a father of three aged 32, Zeydan said.