Secretary of State John Kerry on Thursday told Russia that the U.S. has "concerns" that most of Russia's military actions in Syria are not targeting the Islamic State, and instead are defying U.S. policy by targeting groups that oppose Syrian President Bashar Assad.

Kerry spoke with Russian Foreign Minister Sergey Lavrov on Thursday in a phone call that lasted more than 30 minutes, according to State Department spokesman John Kirby.

"On Syria, the secretary repeated our concerns about the preponderance of targets that are being struck by Russian military forces that are not ISIL related," Kirby said.

Kirby said over the last two days that the U.S. believes more than 90 percent of Russia's military efforts in Syria are aimed at groups that oppose Assad, and aren't targeting the Islamic State.

"[G]reater than 90 percent of the strikes that we've seen them take to date have not been against ISIL or al Qaeda-affiliated terrorists," Kirby said Wednesday. "They've been largely against opposition groups, groups that want a better future for Syria and don't want to see the Assad regime stay in power."

"So whether they're hit by a cruise missile from sea or a bomb from a Russian military aircraft, the result is the same: that Assad continues to get support from Russia," he added.

Despite those "concerns," the Obama administration continues to indicate that its only option is to keep trying to reach a political deal with Russia on how to proceed. That includes reaching an agreement on ways to make sure the U.S. and Russian militaries don't run into each other as they pursue want increasingly seems to be completely different goals in Syria.

"They also talked about the importance of moving forward on tactical discussions and dialogue towards the goal of deconfliction, again, to avoid mishaps and misunderstandings, particularly in the air," Kirby said of Kerry's talk with Lavrov.

Kirby was hesitant to say Russia's actions are bolstering Assad, but finally admitted that the more Russia moves in Syria, the more Assad is being aided.

He said Kerry stressed to Lavrov the importance of finding a political solution that includes a transition to a government "away from Assad."

Secretary of State John Kerry admitted that the more Russia moves in Syria, the more Assad is being aided. in Congress on LockerDome