Negotiators tasked by the Pakistani government to hold peace talks with the Taliban's intermediaries Friday warned that the continued militant attacks could halt the dialogue process. The warning from the came a day after Taliban bombed a police vehicle in Karachi and killed 13 police officers and injured dozens others. Taliban quickly claimed responsibility for the attack, which created doubts about the success of the peace talks. Taliban spokesman Shahidullah Shahid said the attack was aimed at taking revenge for Taliban members who have been "killed in Karachi and other cities in recent days by the police and paramilitary troops." The dialogue committees of the government and Taliban met in Islamabad on Friday to discuss ways for peace and security in the country expressed apprehension that continuation of peace dialogue will become impossible if anti-peace activities continue. "The committees feared that such activities will cast adverse impact on peace efforts," a joint communique issued at the end of the talks said. The government committee asked Taliban to halt such negative activities forthwith and take practical steps for peace. It also apprehended that terrorist incidents like that of Karachi will create negative scenario for the dialogue process. Earlier head of the Taliban committee, Maulana Sami-ul-Haq said he will urge the Taliban to stop attacks for advancement in the peace process. "We will ask the Taliban to stop attacks," Maulana Samiul Haq said in Islamabad on Friday ahead of the second round of peace talks with the government committee. Friday's meeting was the first after a senior member of the Taliban committee had two-day talks in Waziristan tribal region with Taliban leaders who had handed over a letter to him for the government side. The intermediaries said earlier that the Taliban have responded positively to the government's suggestions. Both sides have not disclosed their conditions and mediators said they want the Taliban to stop violence to take the peace process forward. "Enemy and some foreign elements do not want peace negotiations in Pakistan," Maulana Samiul Haq said. Lawmakers have expressed concerns over the recent wave of terror attacks and said it could harm the dialogue process. Leader of the ruling party in the Senate Raja Zafarul Haq has told the Senate that continuing terrorist attacks while holding talks will spoil the process and public support for dialogue will also decline. Speaking on points of order, the opposition members said the government should have conveyed it to the Taliban that for any talks to start they must first suspend their attacks.