- The U.N. Human Rights Council will hold a special meeting Friday
- The Syrian regime says terrorists committed the Houla killings
- The U.S. ambassador to the U.N. calls Syria's account "another blatant lie"
- At least 61 people died in Syria on Thursday, an opposition group says
(CNN) -- One week after ghastly attacks left 108 people dead in one town, defiant protesters are expected to brave the streets of Syria on Friday in what is billed as "a merchants' strike to stop massacring children."
Meanwhile, thousands of miles away in Geneva, Switzerland, the U.N. Human Rights Council will convene in an emergency session Friday to discuss the "deteriorating human rights situation in Syria."
Throughout Syria's nearly 15-month crisis, demonstrators have taken to the streets to express outrage at the Syrian regime and its crackdown on dissidents -- despite the fear of attack at such protests.
This week's theme highlights the success of a nationwide general strike by merchants disgusted with the May 25 slaughter in Houla, said the opposition Syrian Revolution Coordinators' Union. Analysts say an uprising by Syria's merchant class -- part of President Bashar al-Assad's support structure -- could elevate the uprising.
The massacre last week, which left at least 49 children dead, set off a diplomatic firestorm and calls for action against al-Assad's regime.
But on Thursday, Syria attributed the carnage to "armed terrorist groups," the vague entities that the regime has blamed all along for widespread violence against civilians.
"The goal of the armed operation was to completely terminate the presence of the state in the area and to make it one that is out of the control of the state," Qasim Jamal Sleiman, head of the investigative panel, said in televised remarks.
"All of the martyrs are from peaceful families who refused to stand against the state and have never demonstrated or carried weapons against the state. They were in disagreement with the armed terrorist groups, which confirms that there was a goal and an interest to kill them."
But the U.S. ambassador to the United Nations, Susan Rice, called the Syrian account "another blatant lie" and said there's no "factual evidence" to "substantiate that rendition of events." She said the U.N. Human Rights Council in Geneva could soon embark on an effort to establish facts in the case and hold people accountable.
U.S. Defense Secretary Leon Panetta said the international community needs to ensure al-Assad steps down.
"There is no question that we are very concerned about the atrocities that are taking place in Syria," he said. "Just makes clear how important it is to remove Assad from power and to try to implement the necessary political reforms that are necessary in that country."
The Syrian government investigation said 600 to 800 armed people gathered after Friday prayers at two primary locations and committed the crimes. Sleiman said firearms shot from a close distance and sharp objects were used, but there was no shelling -- contrary to what opposition activists have said.
The Local Coordination Committees of Syria, an opposition network, blamed "armed militias" of the Syrian government.
"This barbaric act was preceded by the regime's mortar shelling in the town," the LCC said in a statement. "The campaign ended when the armed militias slaughtered entire families in cold blood."
Survivors corroborated that account to Human Rights Watch, saying the army shelled the area and "armed men, dressed in military clothes, attacked homes on the outskirts of town and executed entire families."
Sectarian tensions have been high in Houla, which is overwhelmingly Sunni and is surrounded by Alawite and Shiite villages. The regime is dominated by Alawites.
U.N. Secretary-General Ban Ki-moon referenced the Houla incident on Thursday in Istanbul, Turkey, saying "the massacre of civilians of the sort seen last weekend could plunge Syria into a catastrophic civil war -- a civil war from which the country would never recover."
Already, the Syrian crisis has left at least 9,000 people dead, according to the United Nations. Other estimates range to more than 14,000.
For months, international leaders expressed cautious hope that a peace plan laid out by U.N.-Arab League envoy Kofi Annan would help stymie the violence.
But on Thursday, at least 61 people were killed in the country, the LCC said. Syrian forces shelled Houla again early in the day, and 29 people were killed in the besieged area of Homs, the group said.
Though reports of deaths mount every day, British U.N. Ambassador Mark Lyall Grant said he was not prepared to pull the plug on the peace plan.
"Clearly, it is on life support, but it isn't dead, yet," he told CNN's Christiane Amanpour on Thursday.
"We are directing all our efforts into trying to make it work," he said. "But I think to make it work we're going to need to increase the international pressure on the Syrian regime."
Grant praised the role U.N. observers in Syria played in bringing the Houla massacre to light:
"To be honest, we would not know exactly what had happened in Houla had it not been for the observers able to go there, to demonstrate that there had been tank tracks, that there had been use of heavy artillery, that there had been a massacre by the Syrian regime," he said.
"Otherwise, people would give some credence to this report that the Syrian government has come out with today claiming that it was nothing to do with them. We know that's a tissue of lies partly because the U.N. observers are able to say so."
Russia and China have been more receptive to the Syrian government during the crisis, and have blocked tough action against the al-Assad regime in the U.N. Security Council.
Russian Foreign Minister Sergey Lavrov said this week that "certain countries" were attempting to use the Houla massacre as a "pretext" for a military operation against al-Assad's forces, which have been partly armed by Russia, Russia's RIA Novosti reported.
CNN cannot confirm death tolls or reports of violence from Syria because the government limits access to the country by foreign journalists.
CNN's Amir Ahmed, Ivan Watson, Holly Yan, Yesim Comert and Omar al Muqdad contributed to this report.
