Up to 20 people have died after tanks armed with machine-guns opened fire on protesters in Syria on Thursday, according to activists and human rights groups.
The incident in the city of Homs was reported by the Syrian Observatory for Human Rights and the global activist network Avaaz.
Avaaz said that the 17 deaths they had recorded were the result of "indiscriminate shootings at passers-by, people's homes or at shops, by security forces and troops stationed checkpoints or driving along in cars".
'Randa', an eyewitness from Baba Amr working with Avaaz, said:
"There is the sound of heavy explosions and shelling. We’ve heard shelling before but it has never been this intense. There’s a general terror and panic amongst residents in Baba Amro and in all of Homs actually.
"We’ve seen reinforcements come in from the direction of the Youth Buildings. At present, there are about 40 army vehicles in the neighbourhood alone. There are tanks positioned outside buildings directly. There are also military vehicles that are not tanks but rather army vehicles with the capability of shooting.
"Baba Amro is small but there are many, many entrances to the neighbourhood and the army has besieged it from all sides.”
Video footage was also released which appeared to show tanks opening fire in civilian areas.
Eyewitness reports said that the neighbourhood of Baba Amr resembled "a war zone" just one day after President Bashar al-Assad said he would agree to an Arab League plan to pull tanks out of civilian areas and cease attacks on protesters.
The Arab League said that authorities in Damascus were prepared to release all political prisoners and start a dialogue with opposition figures within a fortnight.
It was also reported that foreign journalists, human rights groups and Arab League officials would be allowed more free access to the country. Currently very stringent restrictions on foreign reporting in the country are in place - making independent verification of the incidents in Homs difficult.
Activists were sceptical of the announcements made by the Arab League, and said it was little more than an attempt by the government to delay possible repercussions from the international community.
Protests against Assad's government began in March and have resulted in the deaths of at least 3,000 people according to activist groups. Many others have disappeared or been injured.
The protests have become more violent in recent weeks, but the government maintains that the fighting is being carried out by terrorists and armed, organised gangs.
Assad' officials say that more than 1,000 government soldiers have been killed in the violence.