Kremlin Spokesman Dmitry Peskov told a conference call with reporters that Putin had hailed the breakthrough as "a strategic victory” over Daesh (ISIL or ISIS) militants, Reuters reported.
Street-to-street fighting was now underway in Deir ez-Zor, Peskov said.
Russian air strikes that struck Daesh targets in the city on Tuesday helped Syrian government troops and their allies in the area swiftly advance, he said, citing a Russian Defense Ministry report to Putin.
On Tuesday, Syrian security forces advanced against Daesh to reach troops surrounded for years by the terrorists in a government-held enclave in the eastern city of Deir ez-Zor.
State television reported that advancing Syrian forces had linked up with government troops in Deir ez-Zor.
Deir ez-Zor is located southeast of Daesh’s main stronghold Raqqa.
Both cities lie in oil-rich areas on the Euphrates River.
Syria has been gripped by civil war since March 2011 with various terrorist groups, including Daesh, currently controlling parts of it.
According to a report by the Syrian Center for Policy Research, the conflict has claimed the lives of over 470,000 people, injured 1.9 million others, and displaced nearly half of the country’s pre-war population of about 23 million within or beyond its borders.