U.N. officials press world leaders to act immediately to protect Syrians Two U.N. officials demand international community take action on Syria The officials say world leaders need to meet their responsibility to protect civilians "The risk of further mass atrocity crimes is high," the officials said (CNN) -- Senior United Nations officials called on the international community to take immediate action to protect civilians in Syria, citing the failure of President Bashar al-Assad's government to protect its population from atrocities. The call for action follows reports of recent mass killings in two Syrian towns, part of a surge in violence by government and rebel forces in recent weeks as a peace plan put together by Kofi Annan unraveled. With the increasing violence and deepening sectarian tensions, the risk of further mass atrocity crimes is high. The time for action is now," the Special Advisers of the Secretary-General on the Prevention of Genocide and on the Responsibility to Protect, Francis Deng and Edward Luck said in a joint statement Thursday. The two called on the international community to take action to meet its "responsibility to protect populations at risk of further atrocities in Syria," taking into consideration "the full range of tools available under the United Nations Charter." World leaders have been wrangling over what to do about the conflict in Syria, leaving the U.N. Security Council at a standstill over possible action. On one side the United States, the European Union and much of the Arab League, who are demanding al-Assad step down and end the violence. On the other side, Russia, China and other trade allies of Syria, who say the conflict is an internal matter that must be decided by Syrians. The United Nations estimates more than 10,000 people, mostly civilians, have been killed in Syria and tens of thousands displaced since the uprising against al-Assad began some 16 months ago. The opposition puts the toll at between 12,000 and 14,000. CNN cannot independently verify government and opposition claims of casualties because access to Syria by international journalists has been severely curtailed. As a result, the conflict has largely played out as a series of daily countering claims, with the opposition accusing government forces of indiscriminate shelling of residential neighborhoods or other such violence, while the government claims its forces are battling "armed gangs" bent on destabilizing the government. The uprising has its roots in the Arab Spring, with anti-government protests erupting in Syria following popular revolutions in Tunisia and Egypt. Al-Assad's government moved to quash the protest movement, which quickly devolved into an armed rebellion. A peace plan put together by Annan, a joint envoy for the United Nations and the Arab League, that outlined an end to the violence in Syria fell apart within weeks of being agreed upon by al-Assad's government and the opposition, with each side accusing the other of violations. As part of Annan's plan, roughly 300 unarmed U.N. observers are in Syria to monitor whether both sides were abiding by the deal. This week, a U.N. official overseeing monitors in Syria described the violence as a "civil war," the first time anyone with the global body has used such language to describe the uprising. U.N. observers finally entered the northwestern Syrian town of al Haffa Thursday to find it deserted after days of intense fighting. Most government institutions, including the post office, had been set afire from the inside, said Sausan Ghosheh, spokeswoman for the U.N. mission in Syria. Archives were burned, stores were looted and set ablaze, and homes appeared to have been ransacked. The ruling Baath Party Headquarters in al Haffa had been shelled and appeared to have been the site of heavy fighting, Ghosheh said. Government forces fought the rebels in al Haffa and said they had reclaimed the town in Latakia province. The rebels, in turn, admitted to a forced retreat. The London-based Syrian Observatory for Human Rights, an opposition rights group, said al Haffa was shelled for eight days. U.N. observers had attempted to reach the town Monday but were blocked by angry supporters of the government. Now, after seeing the destruction, Ghosheh said, the United Nations reiterated its plea for all parties to put down their guns. Additionally, the recent mass killings of civilians in Houla and Quebir represent "an alarming escalation in targeted attacks against civilians," Deng and Luck said in their joint statement. The two men also urged the U.N. Security Council to consider previous requests to refer the allegations for investigation to the International Criminal Court at the Hague. "These massacres underscore the Syrian government's manifest failure to protect its population," they said. CNN's Saad Abedine and Chelsea J. Carter contributed to this report.