U.N. team investigates reported Syria massacre BEIRUT (AP) - U.N. observers investigated the latest reported massacre in Syria, entering a village Saturday where activists say regime forces killed dozens of people the past week, as Turkey's prime minister blasted Damascus' leadership, warning that the Syrian people will "make them pay" for such mass killings. An 11-vehicle team of observers went into the central village of Tremseh after receiving confirmation a cease-fire was in place, a spokesman for the U.N. mission in Syria, Ahmad Fawzi, said. It is the first outside look into the village where activists say at least 150 people were killed by government troops who shelled the town before moving in alongside pro-regime militiamen. "We have sent a large integrated patrol today to seek verification of the facts," Fawzi said. Details of the killings remain unclear. The Syrian government says 50 people were killed in Tremseh Thursday when its forces clashed with "armed gangs" that were terrorizing village residents. The regime refers to its opponents as terrorists and gangsters. On Friday, the United Nations blamed government forces for the Tremseh assault, saying U.N. observers deployed near the village saw government troops using heavy weaponry and attack helicopters against it. World leaders have heaped criticism on President Bashar Assad's regime over the Tremseh incident, which was the latest in a series of reported mass killings by regime forces in recent months. Anti-regime activists say more than 17,000 people have been killed since the uprising against Assad's rule began in March 2011. The killings cast new doubt over the international community's efforts to find a diplomatic solution to Syria's crisis. The prime minister of Turkey - once an ally of Assad before turning against him early on in the uprising over the regime's bloody crackdown, blasted Syria's leadership on Saturday over the Tremseh killings. "These vicious massacres, these attempts at genocide, these inhuman savageries are nothing but the footsteps of a regime that is on its way out," Recep Tayyip Erdogan said. Sooner or later, these tyrants with blood on their hands will go and the people of Syria will in the end make them pay. A suicide bomber blew up his car in the closest main town to Tremseh on Saturday, killing three civilians and one security officer, Syria's state news agency said. SANA said the attacker, who camouflaged the bomb with onions, detonated the explosives in the town of Muhrada. The anti-regime Syrian Observatory for Human Rights said the bomb targeted the local military security headquarters. Both reports said the dead included two women and a child. The Observatory provided a photo of what it said was the bomb site. It showed the facades blown off buildings on opposite sides of a street. Bombings of security buildings throughout Syria have grown more common as the uprising has turned into a rebel insurgency. Many worry the attacks reflect the rise of Islamist extremists and possiblyal-Qaida in the anti-Assad struggle. Credible claims of responsibility for such attacks are rare, although a shadowy militant group calling itself the Al-Nusra Front has claimed some of them in postings on militant websites. Little is known about the group. The U.N. special envoy to Syria, Kofi Annan, on Friday said he was "shocked and appalled" by the reports of the attack on Tremseh, and condemned the government for using heavy weaponry in populated areas, something it was supposed to have stopped three months ago. Activists said the army surrounded and shelled the village before storming it with pro-government gunmen who killed people in the streets. They provided videos showing tanks in the town and dozens of dead bodies. The government said the army intervened while armed terrorists were harassing the town. On Saturday, the state news agency posted photos of rifles, hand grenades, mortars, cell phones and video cameras it said had been found in the town. Government and activist claims could not be independently verified.