Human rights groups reported the slaughter soon after Russia's foreign minister praised Syrian President Bashar Assad's "commitment" to ending the violence that has overwhelmed the country for 11 months, CNN reported.
Reports on the death toll in Homs range from 20 to 54, CNN said.
"There is non-stop shelling," said Omar Shakir, a Homs resident, who pegged the toll at 54 after he said he visited and called field hospitals in three neighborhoods in the city.
"We cannot count the dead anymore. They want to finish us," Mohammed Salih, another Homs resident, told CNN.
Several media outlets reported 20 members of three families died when soldiers burst into their homes.
The BBC said Homs residents couldn't venture outside to retrieve the dead and injured.
One resident of the Baba Amr area of Homs, said the shelling was indiscriminate.
"Every house here in Baba Amr is a target," the man identified as "Omar" told the BBC. "You have to be lucky to survive."
In a visit to Damascus Tuesday, Russian Foreign Minister Sergey Lavrov said Assad "affirmed his commitment" to an Arab League plan ending the violence "regardless of its source," Syria's state-run news agency reported.
Speaking in Moscow Wednesday, Lavrov announced that Syria's vice president would try to open talks with the opposition and called on Western and Arab leaders to support the effort, The New York Times reported.
"We consider this willingness to be an important factor to be taken into consideration and hope that all who have some kind of influence over the opposition will urge them to begin such dialogue," Lavrov said during a Moscow news conference a day after he was in Damascus.
The Times said Turkey was considering its own initiative to secure a consensus on ending the violence. The Turkish Foreign Ministry said Prime Minister Recep Tayyip Erdogan planned to discuss the crisis with Russian President Dmitri Medvedev in a phone conference.
In Homs, hundreds of people are reported to have died in shelling since Friday, but the reports can't be independently verified because of restrictions the government has placed on foreign journalists.
Violence against protesters was reported elsewhere in Syria, the BBC said. Activists said tanks fired at the town of Zabadani, about 19 miles from Damascus Tuesday and clashes were reported in Hama, another anti-Assad stronghold.
The Syrian regime has blamed violence on armed terrorist groups and thugs.
The United Nations estimates 6,000 people have died since protests began. The Local Coordination Committees, a network of opposition activists, said at least 7,339 people have been killed.
Efforts to pass a U.N. Security Council resolution against the Syrian regime have failed because of vetoes by Russia and China.
Two administration officials told CNN that while the United States is focused on exercising non-military pressure on Syria, Defense Department officials and the U.S. Central Command have started an internal review of U.S. military capabilities should President Barack Obama call for them.
Member states of the Gulf Cooperation Council announced they were recalling their ambassadors from Syria, saying the decision was made "with deep sorrow and anger" at the killings "that did not spare a child, old man, or woman -- heinous acts that can be described as a collective massacre against the defenseless Syrian people without any mercy or pity, and without considering any rights or feelings of humanity or morality."
The United Arab Emirates, Bahrain, Saudi Arabia, Oman, Qatar and Kuwait also expelled Syria's ambassadors from their countries, saying the envoys' presence became ineffective after the Assad regime rejected Arab efforts "to resolve this crisis and stop the bloodshed of the Syrian people."
The United States closed its embassy in Damascus Monday, and several European countries have called their ambassadors home.
White House spokesman Jay Carney said the Obama administration was looking into "providing humanitarian aid" to the Syrian people.
Carney and State Department spokeswoman Victoria Nuland said the administration was not considering armed assistance to the Syrian opposition.
"We never take anything off the table," Nuland told reporters. But "we don't think more arms into Syria is the answer."