Bush said Vladimir Putin was exploiting a vacuum of U.S. leadership in Syria and elsewhere.
The offensive, which both officials said would begin soon, would expand on a ground attack by the same alliance.
Though Putin may look like he’s in control in Syria, the intervention is likely to end badly for him.
The move came weeks after Moscow raised the stakes with its intervention in the long-running civil war.
The new alliance calls itself the Democratic Forces of Syria.
Islamic State fighters have seized villages close to the northern city of Aleppo from rival insurgents.
The much criticized “train and equip” program to fight ISIS and Assad is on pause, probably forever.
Senior U.S. lawmakers have begun probing possible intelligence lapses over Moscow’s intervention in Syria.
If confirmed, the crashes would be a blow to the military strength Russia aimed to display in Syria.
Half the refugees questioned said the Syrian president must go before they could return.
It remains unclear if the missiles caused any deaths.
A Russian lawmaker told Interfax new agency that money may drive Russian soldiers to help Syrian President Bashar al-Assad.
Beyond the future of Assad lies a minefield of questions about risk, escalation and confrontation.
The perpetrators of war crimes and crimes against humanity must not go unpunished.
Sending Russian forces to Syria is a distraction from the problems Putin has with Ukraine.
American officials told The Wall Street Journal that Putin’s primary military goal was supporting the Assad regime.
The strikes seemed to have been carried out near Homs, an area crucial to Assad's control of western Syria.
Adel al-Jubeir said that Assad must either leave voluntarily or face being forced to step down.
Some of the U.S.-trained rebels handed over some of their equipment to Nusra last week in return for safe passage.
"I side with the group that says 'if Russia wants to go and fight ISIS, you should let them,'" Trump said.
Western governments should be warned that including Assad will only prolong the conflict.
The president is calling for a new leader to replace Syrian President Bashar Assad to help defeat ISIS.
The two leaders are to hold face-to-face talks on the Syrian conflict on Tuesday.