Islamic State fighters have killed 26 Syrian soldiers west of Palmyra, a monitoring group says, after days of advances by government forces backed by Syrian and Russian air cover.
Russian President Vladimir Putin said last week that the Syrian army would soon recapture Palmyra from Islamic State, which has held the desert city for nearly a year.
Palmyra has both symbolic and military value as the site of ancient Roman-era ruins - mostly destroyed by the ultra-hardline Islamist group - and because of its location on a highway linking mainly government-held western Syria to Islamic State's eastern stronghold.
The Britain-based Syrian Observatory for Human Rights said on Monday the fighting took place about 4km west of Palmyra.
It was not possible to independently verify the death toll.
Syria's state news agency SANA said the army and allied forces, backed by the Syrian air force, carried out "concentrated operations" against Islamic State around Palmyra and the Islamic State-held town of al-Qaryatayn, about 100km further west.
After more than five months of air strikes in support of Syrian President Bashar al-Assad, Putin announced the withdrawal last week of most Russian forces.
But Russian planes have continued to support army operations near Palmyra, according to the Observatory and regional media, and Putin said on Thursday he hoped that the city would soon fall to the Syrian government.
"I hope that this pearl of world civilisation, or at least what's left of it after bandits have held sway there, will be returned to the Syrian people and the entire world," he said.
Islamic State and the Nusra Front are both excluded from an internationally backed limited truce in Syria, which has been in place for nearly three weeks to allow peace talks to take place in Geneva between the government and opposition groups.