The insurgents, who have made significant gains over the past week, are reported to have breached defenses in the north and east of Homs, the country’s third-largest city.
The rebel alliance also claims its forces are “at the gates” of Damascus, the Syrian capital.
The Polish Embassy in Syria wrote on X on Saturday: “Due to the rapid escalation of the situation, which has quickly spread across the entire territory of Syria, we appeal to all Polish citizens residing in the country to leave immediately.
“We also categorically appeal not to enter the territory of Syria.”
It added: “Polish citizens remaining in Syria should contact the mission via e-mail: damaszek.konsul@msz.gov.pl or emergency phone: +963 944 405 954.”
CNN reported that Syrian President Bashar al-Assad, who has ruled the country for 24 years since succeeding his father in 2000, is “nowhere to be found” in Damascus.
However, the Syrian presidency maintains that the Syrian leader is still in the capital.
Earlier, British newspaper the Telegraph reported that Assad’s family had fled to Russia.