"Now Idlib is our goal, but not just Idlib," Assad said of the northwestern province, in comments carried on Russian newswires.
"There are of course territories in the eastern part of Syria that are controlled by various groups... So we will be moving into all these regions," Assad added.
"The military -- and it is at their discretion -- will decide priorities and Idlib is one of these priorities," he said.
"Now we have liberated Ghouta, we will finish the liberation of the south-western part of Syria," Assad said.
Related: Rojava Kurds will support Assad in Idlib – if it helps them retake Afrin
Syrian government forces launched an offensive last month backed by Russian planes to retake the south of Syria, including Daraa and Quneitra provinces.
Russia, Turkey and Iran have held talks under the Astana peace process launched last year and agreed to create four "de-escalation" zones to pave the way for a nationwide ceasefire.
Idlib is part of one such zone. It borders Turkey to the northwest but is otherwise almost totally surrounded by regime territory, prompting fears the government would eventually attack it.
Idlib has received many rebels and their families evacuated from other regions under Russian-brokered "reconciliation deals" that then saw regime forces move in to take rebel-held areas.
According to the United Nations, Idlib's population today stands at 2.5 million -- half of them displaced people.
In the same interview Assad said rescue workers from the White Helmets group would be killed if they did not turn themselves in.
"Either they can lay down their arms as part of an amnesty ongoing for four or five years, or they will be liquidated like any other terrorist," he said.
Israel on Sunday helped more than 400 people -- opposition-linked White Helmets rescuers and their families -- flee a pocket of southwest Syria as government forces bore down on them. But hundreds more remain trapped in the south, fearing reprisals from approaching regime troops. Damascus accuses the White Helmets of being a front for jihadists.
Assad also appealed for Syrian refugees, especially those who had their own businesses in the country, to return.
The war has killed more than 350,000 people since it began in 2011 with a brutal government crackdown on protesters.
