(CNN) -- Two people died amid protests in Syria on Monday, as government troops and tanks surrounded one town and apparently shelled another for a second day, according to protest organizers and a witness.
One of the deaths occurred in Rastan and the other in Talbiseh, according to the protest organizers known as the Local Coordination Committees of Syria.
The deaths bring to 12 the total number killed since troops entered towns in Homs province early Sunday to end protests against government rule, according to the committee. Ten people, including two children, died Sunday.
CNN has not been granted access into Syria and is unable to independently verify the accounts.
A witness in Rastan, who did not want to be identified for security reasons, said he heard intense explosions beginning around 4 a.m. that lasted for several hours.
Tanks and soldiers have the city completely surrounded, and there is no electricity or water in the city, the witness said.
Despite the siege, protesters took to the streets for about 30 minutes of defiant protest, the witness said.
The Rastan witness said that residents there could hear shelling and gunfire coming from Talbiseh, about 6 miles (10 kilometers) away. But he said it was unclear what was happening there communications have been shut off.
Security forces shelled that city on Sunday as well, with one round striking a school bus carrying children.
In addition to Rastan and Talbiseh, the towns of Deir Ba'albeh and Teir Ma'alleh were also targeted, according to protest organizers.
Syria's government has undertaken a fierce crackdown against demonstrations that have demanded reforms of President Bashar al-Assad.
Roughly 830 people have been killed in the protests, according tot he Syrian Human Rights Information Link. That number does not include security personnel which the Syrian government claims died in attacks from "armed groups."
The United States has imposed new sanctions on al-Assad and other senior Syrian officials, freezing any assets held in the country over human rights abuses.
CNN's Arwa Damon contributed to this report.