Assad's Tanks Move on Aleppo Rebels

Syrian tanks stormed a rebel-held district of Aleppo on Wednesday, sparking fierce clashes that a security official said marked the start of a long-threatened ground assault on the key battleground city.

The assault on the country's commercial capital came as Amnesty International raised concerns about the plight of civilians in the city and warned both sides they would be held accountable for any attacks on civilians.

"The assault has genuinely begun," the security official in Damascus told AFP.

"The army is advancing to cut (the southwestern rebel redoubt of) Salaheddin in two. It will not take long, even if there are still some pockets of resistance."

On Sunday, an official had said the army had massed 20,000 troops for the assault to recover Aleppo, of which the rebels claim they hold half. He said the insurgents had 6,000-8,000 men.

Wassel Ayub, a commander of the rebel Free Syrian Army, told AFP "regime forces advanced into Al-Malaab Street (in Salaheddin) with tanks and armored vehicles, and fierce fighting is now taking place in the area."

A rebel commander said his men were being prevented from mounting a counter-attack by snipers.

The army first shelled several districts of the northwestern city before dawn.

Sixteen civilians were killed in Aleppo and in the rest of the same province, with six more elsewhere in the country, the Syrian Observatory for Human Rights said.

Among the dead were a woman and her two children, killed when a shell struck their house in Al-Mashatiyah neighborhood, the Observatory said.

A total of 225 people -- mostly civilians -- died in Syria on Tuesday. That made it one of the worst days for casualties in the 17-month uprising that the Observatory said last week had cost more than 21,000 lives.

The neighborhoods of Qatarji, Tariq al-Bab and Shaar also came under heavy shelling.

The Syrian Revolution General Council, a network of activists on the ground, reported overnight shelling in the neighbourhoods of Al-Kalassa, Shaar, Sukari and Tariq al-Bab as well as heavy artillery fire aimed at the Bustan al-Qasr and Fardoss districts.

In Lebanon, a dozen shells from the Syrian side of the border struck overnight, causing no casualties, a security official in northern Lebanon said.

Amnesty International showed satellite images indicating an apparent increased use of heavy weapons in the area.

It warned forces loyal to President Bashar Assad that attacks on civilians would not go unpunished.

"Amnesty International is sending a clear message to both sides in the fighting: Any attacks against civilians will be clearly documented so that those responsible can be held accountable," Amnesty's Christoph Koettl said.

The London-based watchdog said images from Anadan, a small town near Aleppo, revealed more than 600 probable artillery impact craters from the fierce fighting over the city.

It said an image from July 31 showed what seemed to be artillery impact craters next to what appeared to be a residential housing complex in Anadan.

Amnesty said it was concerned the deployment of heavy weaponry in residential areas would lead to further human rights abuses and grave breaches of international law.