The opposition Syrian National Council has urged the United Nations Security Council and the Arab League to take action after reports that government troops “massacred” more than 200 people in two days.

The opposition council on Wednesday called for an emergency U.N. meeting to discuss the recent “massacres” in Zawiyah mountain, Idlib and Homs. The SNC says 250 people have died in a 48-hour period, making it one of the deadliest times since the anti-government uprising began in March.

It urged the U.N. to declare these areas “safe zones” and force Syrian troops to withdraw.

In Washington, White House spokesman Jay Carney said Wednesday the overwhelming majority of the loss of life in Syria stems from the actions of Syrian President Bashar al-Assad's government.

He said the U.S. is “deeply disturbed” by credible reports that the government is indiscriminantly killing scores of civilians and army defectors.

An activist with the Syrian Observatory for Human Rights told VOA Tuesday that troops surrounded and attacked civilians, including activists, in the Idlib province village of Kafruwed. In one instance, the London-based group told VOA security forces beheaded the leader of a local mosque.

Witnesses also told the Observatory that troops besieged a group of army deserters in Idlib, killing or wounding as many as 100. Civilian deaths were reported in other areas as well.

The Observatory's claims could not be independently confirmed because Syria has restricted foreign journalists in the country.

The reported attacks come as foreign observers prepare to enter Syria in an effort to end the nine months of bloody unrest.

Arab League officials say an advance team will arrive in Syria Thursday to prepare for the observer mission, which will eventually involve hundreds of monitors. The team will include security, legal and human rights experts.

Syria agreed to allow the observers into the country under global pressure to stop the bloody crackdown on anti-government protesters.

The White House vowed Wednesday that the international community will take steps to pressure Mr. Assad's government if the Arab League peace plan is not implemented.

Critics have said the Syrian move is a stalling tactic. Ian Lustick, a Middle East analyst with the University of Pennsylvania, told VOA that similar scenarios have played out in other countries in the region, and that he doubts the observer mission will occur as planned.

The United Nations says at least 5,000 people have been killed during the nine-month uprising against the government of President Bashar al-Assad. Syrian authorities blame the violence on “armed terrorist groups.”