The Syrian army has launched a broad ground assault on rebel-held areas of the besieged city of Aleppo and activists reported clashes as opposition forces fought back in a battle that has raged for more than two weeks.
Syrian forces pulled back from parts of the district of Salaheddine in the northern city of Aleppo after heavy clashes with rebels fighting to overthrow President Bashar al-Assad, rebel sources said on Wednesday.
"Street warfare took place, they [the rebels] have inflicted huge loses on Assad's forces who pulled back now. Salaheddine is under the control of the Free Army," Omar, an activist in the area, told the Reuters news agency by Skype.
Other rebels confirmed his account.
The rebel version of events, however, appeared to be at odds with a report from Syrian state television earlier in the day which said government forces had pushed into Salaheddine, killing most of the rebels there, and had entered other parts of the city in a new offensive.
Images that have emerged from the northern city showed collapsed buildings, and large craters which activists said were caused by shelling.
Aleppo, the largest city in Syria and its commercial centre, holds great symbolic and strategic importance. Some 40km from the Turkish border, it has been a pillar of regime support during the uprising. An opposition victory there would allow easier access for weapons and fighters from Turkey, where many rebels are based.
"The army is advancing from west to east to cut Salaheddine in half horizontally," an official said on Wednesday on condition of anonymity, referring to the key rebel stronghold in the city.
Wassel Ayub, a commander in the rebel Free Syrian Army (FSA), said: "The regime forces advanced into Al-Malaab Street with tanks and armoured vehicles and fierce fighting is now taking place in the area."
Al Jazeera's correspondent Ahmed Zaidan, reporting from Aleppo, said "a large number of people have been killed or injured in a fierce battle near Salaheddine in which advanced Russian tanks have been used by the government forces".
Zaidan says control of Salaheddine, and Aleppo, is "very important for both sides".
"Aleppo is the second largest city and financial hub of Syria. We shouldn't forget that almost 60 or 70 per cent of the Syrian economy now is on a standstill because there is no life in Aleppo," he added.
"Aleppo battle might decide the future of Syria and the future of the position of the regime."
Clashes have also been reported in Hanano, Tareeq Al Bab and Sha'ar in the besieged city, the UK-based Syrian Observatory for Human Rights (SOHR) said.
The observatory said that the clashes taking place in the streets of Salaheddine and in surrounding areas were the most fierce that the northern city has seen in the nearly 17-month uprising.
SOHR said neighbourhoods of Maysaloun, Sakhour and Tal Rifaat were under shelling by government forces.
The Syrian army has made progress but rebels have not abandoned Salaheddine, our correspondent said, adding that the FSA has shot down a plane and destroyed five tanks in Aleppo.
The army, which has been massing its troops and armour in and around Aleppo since late last month, was moving from west to east, coming from Hamdaniyeh, a district adjacent to Salaheddine, the FSA's Ayub said.
Al Jazeera’s Rula Amin, reporting from neighbouring Beirut, said: "It’s not just symbolic but also where most of Free Syrian Army is concentrated, and for the world it also became symbol of FSA’s major success in getting their hold on this city."
"FSA has been bringing in its own rebels from outside Aleppo from country side e.g. Idlib, Homs because for them it’s a major battle. Salaheddine is also crucial for government, as it has been a pillar of support for the [Syrian] President [Bashar al-] Assad in the last 16 months," she said.
In other developments, Jordanian officials have confirmed that former Syrian Prime Minister Riad Hijab, crossed into Jordan only on Wednesday - two days after his defection was announced - after hiding in the south of the country.
Retired guards among Iran hostages
Meanwhile, the Iranian Foreign Minister Ali Akbar Salehi said on Wednesday that "retired" members of Iran's Revolutionary Guards and army were among 48 Iranians taken hostage in Syria by rebels," the ISNA news agency reported.
Salehi said the former military personnel were exclusively on a religious pilgrimage to Damascus when they were seized on Saturday.
"A number of the [hostages] are retired members of the Guards and the army. Some others were from other ministries," Salehi was quoted as telling reporters as he flew back from Turkey, which he asked for help in freeing the Iranians.
Another senior Iranian official visited Damascus on Tuesday where he met Assad.
Saeed Jalili, a senior aide to Iran's supreme leader Ayatollah Ali Khamenei, told Assad that Iran will continue to back the Syrian government.
During talks with Assad, Jalili said that what was happening in Syria was "not an internal issue".
It is "a conflict between the axis of resistance on one hand, and the regional and global enemies of this axis on the other," Jalili said.
On Monday, while on a visit to Beirut, the Lebanese capital, Jalili issued a veiled warning to countries backing the rebels.
"Those who believe that, by developing insecurity in the countries of the region by sending arms and exporting terrorism, they are buying security for themselves are wrong," Iran's official IRNA news agency quoted him as telling Adnan Mansour, Lebanon's foreign minister.