President Bashar al-Assad's forces renewed a ground and aerial bombardment of Aleppo today, extending efforts to crush rebels in Syria's commercial capital in what the United States said it feared could become a massacre.
Insurgents targeted army roadblocks and security installations, with both sides avoiding close-quarters warfare in the city of 2.5 million people, Syria's biggest urban centre.
A rebel commander said insurgents had attacked a convoy of Syrian army tanks heading towards the city, as the government continued to redeploy forces from other parts of the country to bolster its forces there.
The US State Department said credible reports of tank columns moving on Aleppo, along with air strikes by helicopters and fixed-wing aircraft, represented a serious escalation of Dr Assad's efforts to crush a rebellion that began 16 months ago.
"This is the concern: that we will see a massacre in Aleppo, and that's what the regime appears to be lining up for," State Department spokeswoman Victoria Nuland said.
British Foreign Secretary William Hague has today described the assault on the city as an "utterly unacceptable escalation" of the conflict which “could lead to a devastating loss of civilian life and a humanitarian disaster”.
Troops stationed on the outskirts of Aleppo unleashed barrages of heavy-calibre mortar rounds on the western neighbourhoods of Saladin, al-Sukkari and al-Fardos, while Russian MI-25 helicopter gunships struck al-Sakhour in the east with rockets, several opposition activists in the city said.
In the first reported casualty today, a man of about 60 wearing a traditional white prayer outfit was killed near a park in Saladin. His body was placed in a mosque pending identification.
Thirty-four people were killed in Aleppo and its environs yesterday, according to opposition activists keeping a tally of casualties in the northern city.
The heavy fighting around Aleppo follows an audacious bomb attack that killed four of Dr Assad's closest lieutenants in Damascus on July 18th and led some analysts to speculate that the government's grip was slipping.
With UN Security Council resolutions for sanctions against Syria vetoed by Russia and China for a third time last week, the United States has said it is stepping up assistance to Syria's
fractured opposition, although it remains limited to non-lethal supplies such as communications gear and medical equipment.
Reuters has learned that the White House has crafted a presidential directive, called a "finding," that would authorise greater covert assistance for the rebels, while still stopping short of arming them.It is not clear whether president Barack Obama has signed the document, and US officials declined to comment on the finding, which is a highly classified authorisation for covert activity.
Syrian parliamentarian representing the northern province of Aleppo said today she had defected to Turkey, becoming the first member of the rubberstamp assembly elected in May and dominated by president Bashar al-Assad's Baath Party to defect.
"I have crossed to Turkey and defected from this tyrannical regime ... because of the repression and savage torture against a nation demanding the minimum of rights," Ikhlas al-Badawi told Sky News Arabia.
One of the most senior figures to defect from Assad's inner circle, brigadier general Manaf Tlas, put himself forward yesterday as someone who could help unify the opposition inside
and outside Syria on a plan for a transfer of power. Mr Tlas, speaking in a newspaper interview in the Saudi city of Jeddah, also said he was looking for support from Saudi Arabia and other powers.
"I am discussing with ... people outside Syria to reach a consensus with those inside," Mr Tlas told yesterday's edition of the Saudi newspaper Asharq al-Awsat.
Mr Tlas went on to Turkey and met with foreign minister Ahmet Davutoglu. Turkey, a former ally of Dr Assad and now one of his fiercest critics, has a heavy strategic stake in shaping any post-Assad leadership in neighbouring Syria.
Turkey closed its border posts with Syria on Wednesday to all traffic except Syrian refugees.
Russia, one of the few remaining allies of the authoritarian Dr Assad whose family has run Syria for 42 years, said calls for him to quit power were hindering efforts to end the conflict.
Foreign minister Sergei Lavrov said such calls, led by the United States, Turkey and other Western and Arab nations, were fanning violence. He reiterated Moscow's contention that support for Syrian rebel groups was tantamount to backing terrorism.
Iran promised to stand by Syria, come what may.First vice president Mohammad Reza Rahimi told Iran's Press TV yesterday that the Islamic Republic's support for Syria, its main Arab ally, was "unchangeable", countering suggestions that Iran could soften its backing for Dr Assad.
Rebels have detained scores of Syrian officers, soldiers and pro-government militiamen this week in Idlib province and in the city of Aleppo, the opposition Syrian Observatory for Human Rights said today.
A video posted on YouTube showed rebels with Kalashnikovs in Aleppo from "The Tawheed (monotheism) Brigade" guarding the detainees who were lined up in four groups on a school playground.
An off-camera voice said they had been detained in Aleppo, Syria's biggest city.Some of the detainees' faces were covered with bruises and showed signs of swelling around their eyes and when they spoke their voices quavered.
One said he was a colonel, another a major and several identified themselves as shabbiha, a term used by opposition to describe militiamen who are loyal to Dr Assad and are fighting alongside his troops.At the end of the video, a rebel voice said: "The Free Army will terminate all the shabbiha, God willing."
A rebel from the group told the Reuters news agency that the detainees were safe and have been moved to an unidentified site in the countryside around Aleppo, which is a rebel stronghold.
"Some were detained in the Shaar police station and others have surrendered," he said."They are still alive, they will stay with us until the regime is toppled and then they will be put before a trial, each one will get what he deserves."