Syrian government forces backed by Russian airstrikes have taken the high ground around Palmyra and positioned themselves to recapture the historic town held by Islamic State.
The troops, supported by pro-government militias, approached to within three kilometres of the town, according to state TV.
A Lebanese television station close to Damascus broadcast footage of the troops advancing single-file through a desert as helicopter gunships provided cover.
"God willing, within a few hours we will enter and secure the town," one officer told the Syrian Ikhbariya TV, as a group of soldiers broke into chants in support of President Bashar Assad.
The station was broadcasting live from a road reportedly on the outskirts of Palmyra.
The town is home to impressive Roman-era ruins and was one of Syria's leading tourist attractions before the 2011 uprising.
IS captured Palmyra last May and has destroyed some of the ancient monuments.
In Geneva, meanwhile, the EU foreign policy chief held a rare meeting with Syria's UN ambassador, who is leading the government's delegation at UN-mediated peace talks.
Federica Mogherini said Brussels still insists on a political transition in Damascus as part of efforts to wind down the five-year civil war.
"Obviously not all our exchanges were consensual. But I thought it was important to bring the EU consolidated position that we expect the political process and transition to start," she told reporters.
Since the outbreak of the civil war, European diplomats have rarely met with Syrian officials, many of whom are subject to US and EU sanctions.
The government forces have been advancing on Palmyra since last week. Recapturing the town would be a major victory for Assad.
Russia began withdrawing most of its forces and aircraft from Syria last week after a months-long bombing campaign that succeeded in turning the tide of the war again in the government's favour.
Moscow says it will keep its bases in Syria and continue to carry out airstrikes against IS and other extremists.
Syrian forces are pushing in from the west and south of Palmyra and are also closing in on the IS-held town of Qaryatain in central Syria, Homs governor Talal Barazi said.
"There is continuous progress by the army from all directions," Barazi told The Associated Press by phone, adding that he expected "positive results" over the next few days.
IS destroyed many of Palmyra's Roman-era relics, including the 2,000-year-old Temple of Bel and the iconic Arch of Triumph.
It also killed dozens of captive Syrian soldiers and dissidents in public slayings at the town's grand Roman theatre and other ruins.
IS also demolished Palmyra's infamous Tadmur prison, where thousands of Syrian government opponents had been imprisoned and tortured over the years.