DAMASCUS - UN envoy Staffan De Mistura held talks in the Syrian capital on Saturday to try to finalise a deal to freeze fighting in the war-ravaged second city of Aleppo.
About 220,000 people have been killed in Syria since the conflict began in March 2011
He met Foreign Minister Walid Muallem and agreed to send a delegation from his Damascus office to Aleppo on a fact-finding mission, state news agency SANA said, without giving a date.
De Mistura's visit started as the army and pro-regime fighters regained territory in southern Syria from forces opposed to President Bashar al-Assad.
The Swedish-Italian diplomat "hopes to set in motion as soon as possible his project" to halt fighting in Aleppo for six weeks, said a member of his delegation who spoke on condition of anonymity.
He has met government officials and opposition chiefs in recent weeks to promote his plan for a temporary truce in Aleppo in order to move aid into the northern city.
Once Syria's commercial hub, Aleppo has been devastated by fighting that began in mid-2012, and the city is now split between loyalist forces and rebels.
De Mistura said last week that the government had shown a willingness to suspend aerial bombardment of Aleppo for six weeks to allow a humanitarian ceasefire.
Under the plan, rebels would be asked to suspend rocket and mortar fire there during the freeze.
De Mistura incurred the wrath of the opposition earlier in February by describing Assad as "part of the solution" to Syria's conflict.
About 220,000 people have been killed in Syria since the conflict began in March 2011 with anti-government protests that spiralled into a multi-sided civil war drawing foreign jihadists.
- Iranian advisers -
In Daraa province southwest of Damascus, regime troops backed by Lebanese Shiite militant group Hezbollah, Iranian advisers and Iraqi militiamen gained territory from opposition rebels and Al-Nusra Front, the Syrian Observatory for Human Rights said Saturday.
The pro-regime forces took control of three villages and several hills in Daraa in clashes that left seven rebels dead, the Britain-based monitor said.
Hezbollah and regime forces launched an operation earlier this month to try to reverse sweeping gains in the south made by anti-Assad rebels and Al-Qaeda's Syria affiliate, Al-Nusra Front.
In northern Syria, meanwhile, dozens of people were killed in fierce fighting that broke out on Friday between Al-Nusra Front and US-backed rebels for a strategic northern military base.
At least 29 fighters from the Western-armed Hazm movement died along with six Al-Nusra Front jihadists, according to the Observatory.
"Al-Nusra captured Base 46," Observatory director Rami Abdel Rahman said of a sprawling military compound rebels seized in November 2012 from loyalist troops.
- Coalition strikes -
The Observatory also reported that a "court" of the Islamic State group near Tal Tamr in Hasakeh province had ordered the release of 28 Assyrian Christians from at least 220 abducted by the jihadists earlier in the week.
The Pentagon said US-led coalition aircraft carried out nine air strikes against IS in Syria in the 24 hours to 0600 GMT Saturday.
De Mistura's visit to Damascus coincides with a meeting of the main opposition National Coalition in the Turkish border town of Kilis to discuss the Aleppo freeze plan, an alliance spokesman said.
Those at the meeting include coalition chief Khaled Khoja, opposition figures and representatives of Aleppo's civil society.
It would run into Sunday and conclude "with an announcement on the creation of a follow-up committee that will make contact with de Mistura about his project," said the spokesman.
When he revealed his plan this month, de Mistura said he had asked the government to allow a UN team into Aleppo to identify a district for a trial ceasefire.
Syrian Deputy Foreign Minister Faisal Muqdad told Al-Watan newspaper that the envoy suggested the trial begin simultaneously in Salaheddin and Saif al-Dawla, two battleground districts in southwest Aleppo divided between loyalist forces and rebels.
French parliamentarians who met Assad on Wednesday have said the embattled leader expressed support for the plan which De Mistura has been mulling since his appointment in July.
Meanwhile, members of the tolerated domestic opposition, meeting in Damascus on Saturday, did not endorse a roadmap its delegates had agreed in Paris last week with the opposition coalition in exile, apparently because of disagreement over the role of the Muslim Brotherhood.
One participant said they were continuing to "seriously study the document" ahead of a key meeting scheduled for April 17 in Cairo.