KABUL, March 28 (Xinhua) -- Up to 12 police personnel have reportedly been killed in the southern Zabul and neighboring Helmand province on Thursday amid peace efforts to find negotiated end to Afghanistan's protracted fighting.

The militants, as a sign of mounting pressure on security forces targeted police checkpoints in Siory district of Zabul province early Thursday, leaving seven police dead, head of Provincial Council, Ata Jan Haqbayan has confirmed.

Provincial government's spokesman Gul Islam Sayal has also confirmed the attack but said "both sides have suffered casualties," adding investigation has been initiated into the case.

This is the second attack on police in a single day on Thursday that has inflicted casualties on the personnel of law enforcing agency.

In a similar deadly offensive on police force, militants stormed a checkpoint in Pozak area of Kajaki district in the southern Helmand province, killing five police personnel and injuring two others, provincial police spokesman Zaman Hamdard said.

According to the officials, Taliban militants have also suffered in the fighting.

Fighting often gets momentum in spring and summer in Afghanistan commonly known as fighting season among Afghans.

Taliban militants' latest deadly offensives are taking place amid media reports that the U.S. special envoy for peace in Afghanistan Zalmay Khalilzad had resumed his efforts and embarked on a seven-nation trip Monday to muster support for succeeding peace talks with the Taliban.

Taliban militants who had held five rounds of direct talks with the United States since November last year have rejected to hold negotiation with the Afghan administration.

Afghan government's Chief Executive Abdullah Abdullah on Wednesday described the Taliban outfit as "obstacle for bringing peace" in Afghanistan, saying the militant group by refusing to talk with Afghan government wants to re-establish its so-called Islamic Emirate, which is unacceptable to Afghans.