UNITED NATIONS - The United Nations said late Friday it reached an agreement with Syria on an inquiry into the use of chemical weapons, but did not say UN inspectors would be allowed in.

Two UN envoys went to Damascus on Tuesday and Wednesday and held talks with Syria’s deputy prime minister and foreign minister, read a brief UN statement.

“The discussions were thorough and productive and led to an agreement on the way forward,” added the statement, without giving any other detail.

Ake Sellstrom, the chief inspector in the UN investigation team, and Angela Kane, the UN high representative for disarmament, were to report to UN leader Ban Ki-moon on the trip.

Ban has demanded widespread access to investigate all allegations of the use of chemical weapons in the 28-month-old conflict. Syria has insisted that the UN only investigate its claim that opposition rebels used chemical weapons in the town of Khan al-Assal on March 19.

The UN says it has received reports of 13 attacks in the conflict. Britain, France and the United States say all the attacks were carried out by President Bashar al-Assad’s forces. Russia, Assad’s main ally, says its inquiry found opposition rebels used sarin gas in Khan al-Assal.

Meanwhile, regime forces backed by Hezbollah now control half of the Khaldiyeh district of Homs after ousting rebels in fierce fighting in the central Syrian city, a watchdog said on Saturday.

“Loyalist forces backed by fighters from Hezbollah have advanced over the last 24 hours and now control 50 percent of Khaldiyeh,” the Syrian Observatory for Human Rights said.

Its chief Rami Abdel Rahman told AFP on Saturday that overnight, “there was continuous heavy mortar and artillery fire” and that the rebel district was still being pounded. He said rebels were putting up “fierce resistance” amid “very intense clashes”.

Militant network the Syrian Revolution General Commission also reported heavy fighting in the district that has been besieged by regime forces for more than a year.

“Khaldiyeh is being targeted by an uninterrupted heavy bombardment, and on the ground there is fierce fighting between Free Syrian Army fighters and regime forces backed by Lebanon’s Hezbollah trying to take the district,” an SRGC statement said.

It and the Observatory both said the Old City district of Homs - dubbed the “capital of the revolution” against President Bashar al-Assad - was being pummelled too.

The latest regime offensive on besieged rebel-held neighbourhoods of Homs is now in its fourth week.

Government forces are seeking to secure another victory like the one in Qusayr near the border with Lebanon in June, when Hezbollah was key in retaking the strategic town.

Hezbollah, the most powerful military force in Lebanon and a staunch ally of the Assad regime in Syria, has had its military wing blacklisted by the European Union as a terrorist group.