Mafraq, Jordan - Every day, rockets and mortars fired by regime forces rattle the streets of Homs. Armed rebels ambush government military checkpoints. Hatreds brew on either side of the avenues that divide the bloodstained Syrian city.

Homs has become the focus of the worst violence of the 11-month-old uprising, which appears to be morphing into a civil war with fearsome sectarian overtones. Syria's third-largest city has become the major center of both resistance and reprisal, fueled in part by increasingly bold army defectors who want to bring down President Bashar Assad's autocratic regime by force.

Early in the uprising, residents tried to recreate the fervor of Egypt's Tahrir Square, only to face siege upon siege by government forces for nearly a year. Homs now is a powerful symbol of the revolution.

With many neighborhoods outside government control, the regime's tanks and snipers are again opening fire in an offensive that began early Saturday to root out pockets resistance and retake control of an area that holds great strategic importance in Syria.

"You'll be shot dead, if you go out," Samar Rahim, 32, told The Associated Press in this Jordanian farming town along the Syrian border, one week after she fled Homs with her family. "Snipers are firing at anyone in the streets. That's why we left everything behind."

Rahim and other refugees interviewed by the AP described living in fear, hunkering down inside their Homs and desperately trying to protect their young children.

A woman who was three months pregnant was shot and killed when she ventured out for an errand, Rahim said. A 10-year-old boy on her street also was killed. Another neighbor was shot immediately when she opened her front door.

Homs, a city of about 1 million, has shown great sympathy for the opposition since the early days of the uprising. In April, protesters carried mattresses, food and water to the main Clock Square, hoping to emulate Cairo's Tahrir Square, where activists demanded the downfall of the Mubarak regime.

Security forces quickly raided the encampment, shooting at protesters and chasing them through the streets for hours. The onslaught only increased the intensity of the protests, fueling a revolt that has posed the most serious challenge to the Assad family dynasty.

But as the conflict turns more violent, Homs has become the bloodied epicenter. The city shelters a large number of military defectors known as the Free Syrian Army, and many parts of Homs are outside of government control.

It also holds a now-explosive sectarian mix, with a majority from the Sunni Muslim community - which has been the backbone of the uprising - and large communities of Alawites, the Shiite offshoot sect that has stood firmly by Assad, himself an Alawite. Some of Homs' most hardcore opposition neighborhoods, such as Sunni-dominated Baba Amr and Khaldiyeh, lie next to Alawite districts, and revenge killings have broken out.

The city is the capital of Syria's largest province, stretching from the Lebanese border to the Iraqi frontier. If rebel forces keep gaining ground there, some believe they could ultimately carve out a zone akin to Libya's Benghazi, where rebels launched their uprising.

Over the years, many Syrians have referred to Homs as "mother of the poor" because the cost of living is lower. As in the other uprisings sweeping the Arab world, economic hardship has played a role in mobilizing the protests.

Now, Homs is better known as the capital of the Syrian revolution.

In the latest operation, which began Saturday, government forces have unleashed a relentless offensive against Homs, shelling residential areas as they try to root out any resistance and retake control of the city. Hundreds are believed to have been killed there in the last five days.

According to Associated Press Television News video from recent days, rebels move carefully from one position to another overlooking suspected sniper hideouts.

"We don't have the same capabilities to retaliate with the same power," one of the fighters said. Assad's forces have tanks "and we only have this rifle," he added.

In the Baba Amr neighborhood, doctors at a crowded medical clinic struggled to cope with the dead and wounded. "Bashar is a dog," one man spat as he approached a bed where an injured man was treated.

Outside, bodies wrapped in white sheets were piled on a pickup truck. Despite the risk of attack, residents are still holding funeral processions. One corpse was carried through the streets on a truck on a recent day as mourners recited prayers and fired their guns.

Amateur video posted online by activists Wednesday showed empty streets with black smoke billowing from residential areas, with the sounds of explosions and crackle of gunfire in the background. Women and children are seen running for safety.

"God is great against you, Bashar!" an activist shouted after a shell slammed into a home.

The U.N. estimates that 5,400 people have been killed in Syria since the uprising began in March. But that figure is from January, when the U.N. stopped counting because the chaos in the country has made it all but impossible to check the figures.