“Homs is shaking with the sound of explosions from tank shelling and heavy machineguns in the Bab Amro neighborhood,” Najati Tayara said by telephone from the city.

Tayara said a Syrian Christian was killed by sniper fire to his head as he stood in front of his house in the nearby Inshaat district. There was no immediate comment from Syrian authorities who have banned most international media from Syria.

In the south, four civilians in the southern town of Tafas were killed as security forces widened a campaign of arrests, a human rights campaigner in the region said, adding 300 people had been detained since tanks arrived there Saturday.

In Damascus, security forces have arrested opposition leader Mazen Adi, from the People’s Democratic Party founded by Syria’s top dissident, Riad al-Turk, rights activists said.

They added that thousands of pro-democracy Syrians had been arrested and beaten in the last two months, including scores Thursday in Homs and in the coastal city of Banias.

Assad initially responded to the unrest, the most serious challenge to his 11-year grip on power, with promises of reform and assertions that the demonstrators were serving a foreign conspiracy to sow sectarian strife.

He also lifted a 48-year state of emergency that security services had used to suppress any manifestation of dissent.

The state news agency SANA said Thursday a government committee had been formed to draft a new election law, but gave no details.

But Assad has also dispatched troops to crush dissent, first in Daraa where people first took to the streets on March 18, then to some other cities.

He made clear he would not risk jeopardizing the tight control his family has held over Syria for the past 41 years.

Assad’s father, Hafez Assad, amended the Syrian Constitution in the 1970s to make the Baath Party, in power since 1963, “leader of the state and society.”

A cousin of the president said the Assad family was not going to capitulate.

“We will sit here. We call it a fight until the end ... They should know when we suffer, we will not suffer alone,” Rami Makhlouf told the New York Times.

Makhlouf, a tycoon in his early 40s who owns several monopolies, and his brother, a secret police chief, have been under specific U.S. sanctions since 2007 for corruption.

Rights campaigner Suhair al-Atassi said protest action broke out Tuesday in Homs, despite a heavy security clampdown, after tanks stormed several neighborhoods Sunday and three civilians were killed.

“This regime is playing a losing card by sending tanks into cities and besieging them. Syrians have seen the blood of their compatriots spilled. They will never return to being non-persons,” she told Reuters.

Demonstrators have shouted the name of Makhlouf as a symbol of graft in a country that has been facing severe water shortages and unemployment ranging from government estimates of 10 percent to independent estimates of 25 percent. Makhlouf says he is a businessman whose companies provide jobs for thousands of Syrians.

Until the uprising began, Assad had been emerging from Western isolation after defying the United States over Iraq policy and reinforcing an anti-Israel bloc with Iran.

In Banias, protesters held up pictures of Turkish Prime Minister Tayyip Erdogan to salute him for his stand against what they perceive as Assad’s iron fist policy toward opposition.

Erdogan, whose country is one of the few parliamentary democracies in the region, has maintained close trade and diplomatic ties with Assad. But Erdogan has also disputed the official Damascus account of recent political violence in Syria.

Syrian officials have blamed most of the violence on “armed terrorist groups,” backed by Islamists and foreign agitators, and say about 100 soldiers and police have been killed.

Erdogan said more than 1,000 civilians had died in Syria’s upheaval. He said he did not want to see a repeat of the 1982 bloodshed in Hama, where Hafez Assad brutally crushed an Islamist uprising, or the 1988 gassing of Kurds in the Iraqi town of Halabja during the dictatorship of Saddam Hussein.

In Geneva, U.N. Secretary-General Ban Ki-moon urged Syria to halt mass arrests and to heed calls for reform. Ban also said that U.N. humanitarian workers and human rights monitors must be allowed into Daraa as well as other cities.