"President Obama was clear that we intend to continue our efforts to degrade and ultimately destroy ISIL in Syria and to keep supporting the moderate Syrian opposition," the official said.
The White House had multiple national security meetings this week on Syria, the official added.
But the official declined to comment on what steps are being taken to support the opposition, citing "operational security."
Obama's commitment to continue backing the forces fighting President Bashar al-Assad comes as Russia has intervened in the country's civil war
. Moscow says it is targeting ISIS positions, but U.S. Defense Secretary Ashton Carter said Wednesday that the first wave of Russian airstrikes appear to have occurred "in areas where there probably were not ISIL forces."
The U.S. wants Assad to yield power in Syria, a position Russia opposes.
Obama said Friday that he was willing to work with Russian counterpart Vladimir Putin
on moving Syria away from civil war, but only if that plan includes removing Assad from power.
In the absence of that, he warned that Russia's air campaign against Syria would only lead to further bloodshed for the war-torn country and bog down Moscow.
Russia, he predicted during a White House press conference, would get stuck in a "quagmire," adding, "It just won't work, and they're going to stay there for a while."
Obama said Friday he didn't think anyone was "fooled" by Putin's strategy in Syria, which he said amounted to supporting Russia's sole "client state in the Middle East."
He said that during his meeting with Putin at the United Nations earlier this week, he underscored the importance of transitioning Assad from power.
Russia continues to bomb Syrian targets
. On Saturday, the Russian defense ministry said its soldiers bombed nine ISIS positions as part of 20 airstrikes over 24 hours near the terror group's de facto capital in Raqqa.
Tactical bombers destroyed various militant facilities, including ammunition and oil depots, and all-terrain vehicles, the defense ministry said in a statement.