Syrian troops backed by Russian airstrikes have taken up strategic positions around the historic site of Palmyra, which is held by Islamic State militants.
Russia's defense ministry said on March 26 that Russian jets carried out 40 air sorties near Palmyra in the past day to support the government offensive, killing over 100 militants.
Syrian troops and allied militiamen have taken up positions in the three neighborhoods that are part of the modern town of Palmyra, according to the Syrian Observatory for Human Rights, a Britain-based monitoring group.
The statements come as the Syrian government's drive to retake the UNESCO heritage site from IS militants enters its fourth week.
At least 56 government soldiers are reported to have died in fighting this week.
Palmyra, world famous for its Roman-era ruins, fell to IS in May. IS later demolished some of the ancient city's best-known monuments, claiming they promote idolatry.
Retaking the town would be a major victory for President Bashar Assad's government, which has made steady gains in recent months against IS and opposition rebel groups.
Damascus has been assisted in large part by Russia's air campaign.
Earlier this month, Russian President Vladimir Putin ordered a surprise partial pullout of some Russian warplanes from Syria, but said that strikes against IS militants and the Al-Qaeda linked Al-Nusra Front would continue.
Those groups have been excluded from a U.S.-Russian brokered ceasefire that began on February 27 and has largely held.
If Syrian government forces retake Palmyra, they will be positioned to advance on the two largest cities held by IS, Deir Ezzor and Raqqa.
The IS group is on the back foot in Iraq and Syria, where forces on the ground have been backed by U.S.-led airstrikes against the extremists.
The U.S.-led international coalition estimates that the group has lost 40 percent of the territory it once held in Iraq and around 20 percent of its territory in Syria.