Government warplanes pounded a rebel-held neighbourhood in the central city of Homs today, killing at least three and wounding dozens, Syrian opposition activists said. President Bashar Assad's forces also pushed ahead in Syria's offensive on the historic central town of Palmyra that is held by the Islamic State group. The Britain-based Syrian Observatory for Human Rights and pro-government media said troops were about 9 kilometres west of Palmyra, which is home to some of the world's most treasured archaeological sites. IS overran Palmyra, prized for its ancient Roman archaeological ruins, for a second time in December. In March last year, government forces had captured the town ending a 10-month rule of terror by the extremists. The Observatory said government forces and their allies now control hills that oversee three gas fields west of the town amid intense airstrikes. Syrian troops and their allies launched a wide offensive toward Palmyra in mid-January under the cover of Russian airstrikes. The government-controlled Syrian Central Military Media confirmed that troops are now a few kilometres away from the town, which is home to the UNESCO heritage site for which Palmyra is famous and which has already suffered massive destruction at the hands of IS. You may also like to watch this video: IS has been under pressure in Iraq and Syria over the past months and the march toward Palmyra comes days after the extremists lost the northern town of al-Bab that is now held by Turkish troops and Turkey-backed opposition fighters. Iraqi forces are also on the offensive to capture the western part of the northern Iraqi city of Mosul. SCMM said that Syrian troops captured the town of Tadef from IS on the southern edge of al-Bab, adding that military experts are now dismantling explosives and booby-traps left behind by the extremists. Palmyra is in the central province of Homs where violence was reported today in the provincial capital that carries the same name. Also, the United Nations envoy for Syria met with opposition representatives separately in Geneva today reflecting the groups' struggle to form a united front in peace talks with the Damascus government. Staffan de Mistura met first with the representatives of the opposition delegation dubbed the Cairo platform. Opposition activists said airstrikes on Homs' rebel-held neighbourhood of al-Waer today came a day after the area was subjected to more than 40 air raids that killed and wounded dozens. The airstrikes appear to be in retaliation for militant attacks in the city yesterday that killed a senior security officer and at least 31 others.