The epicenter of the Syrian uprising is now under virtual seige by the Syrian armed forces, according to activists.

At least 5 neighborhoods in the city of Homs are under attack and Syrian forces are beginning to surround the entire city.

CNN:

Syrian troops shelled restive neighborhoods Saturday during a massive push in the city of Homs, activists said.

An onslaught occurred in the flashpoint neighborhood of Bab Amr, said activists Abu Omar, based in the western city, and Alexander Page, speaking to CNN from Cairo, where he is in touch with people in Homs. Omar and Page said thousands of troops entered Homs.

"They are surrounding the area from everywhere," Omar said. As CNN spoke to him by phone, heavy gunfire could be heard in the background.The operation occurred as the Arab League prepared to start its monitoring mission next week, part of an initiative to end the violence in Syria.

Another activist in Homs, Abu Salim, said at least 4,000 security personnel were surrounding Bab Amr and the number was increasing. The troops dug trenches around parts of the neighborhood.

He said the neighborhood's population before the security forces arrived was at least 50,000. Now, many people have fled, fearing death and escaping the harsh humanitarian conditions.

"Much of the shelling in the city is coming from the local headquarters of military intelligence in the city. They shell different neighborhoods from there," Salim said. "Tanks are present in some neighborhoods and they directly shoot at homes."

Some western analysts believe Assad will try and break the back of the rebellion in Homs before Arab League observers have the opportunity to go to the city. He's making a good start of it with the shelling, as well as snipers shooting at women and children.

The bombings in Damascus that killed 44 on Friday as well as the continued bloodletting in cities like Homs point to a weakening of the Assad regime that may prove fatal in the near future.