DIYARBAKIR, Turkey (Reuters) - Turkish security forces have killed more than 5,000 militants belonging to the outlawed Kurdistan Workers Party (PKK) since its ceasefire with the Turkish state collapsed last July, President Tayyip Erdogan said on Monday.

Turkish President Tayyip Erdogan addresses the war academy in Istanbul, Turkey March 28, 2016, in this handout photo provided by the Presidential Palace. REUTERS/Kayhan Ozer/Presidential Palace/Handout via Reuters

The figure would suggest a major blow to an organization that has waged its armed campaign for autonomy in Turkey’s mainly Kurdish southeast region since 1984.

Erdogan also told the Turkish armed forces’ War Colleges in a speech that 355 state security forces had been killed in the period, according to the state-run Anadolu Agency.

The southeast has been gripped by violence since July, with the security forces battling the PKK and its youth wing, known as the Patriotic Revolutionary Youth Movement (YDG-H), in densely populated urban centers. The fighting has marked the deadliest period in at least two decades of the insurgency.

On Monday, a local elected official in Sarioren, in Sanliurfa province, was shot dead after suspected militants hijacked his car, security sources said. They were fleeing after detonating an explosive targeting a military vehicle. Three soldiers were hurt in the explosion, they said.

The military said 25 PKK militants were killed in the towns of Nusaybin, Sirnak and Yuksekova in clashes at the weekend.

On Sunday, two soldiers were killed and seven wounded in Nusaybin, which is on the Syrian border, when militants detonated explosives in a building that security forces were searching, security sources said. Five soldiers were wounded.

In a separate incident in Nusaybin, which has been under a round-the-clock curfew since March 14, a soldier was killed by sniper fire, and a police officer was killed in a bomb attack.

It was not possible to independently verify the figures Erdogan gave. Anadolu did not say whether it included Turkish Air Force strikes on PKK camps in northern Iraq.

The military has in years past estimated the PKK’s total fighting force at about 5,000, counting the guerrillas’ ranks in rural Turkey and northern Iraq.

Security sources said the YDG-H had suffered a larger share of the losses since July. Analysts have said the PKK continues to attract new fighters in large numbers.

Turkey’s opposition Peoples’ Democratic Party (HDP), which takes much of the Kurdish vote, says some 500 civilians have also been killed in the military operations which were stepped up in December. That figure has also not been independently verified.