Russia can't bomb its way to Syria peace: Obama

Says attempts to prop up President Bashar al-Assad will fail

US President Barack Obama today warned Russia they could not "bomb their way" to a peaceful solution in Syria, reiterating his view that propping up President Bashar al-Assad will fail.

Speaking after US and Russian militaries reached a tentative deal to prevent mid-air clashes over Syria, Obama said there had been "no meeting of the minds in terms of strategy."

"They are not going to be able to bomb their way to a peaceful situation inside of Syria," Obama told a joint press conference with visiting South Korean President Park Geun-Hye.

His comments come as Russia steps up its bombing campaign in support of Assad and US officials say as many as 2,000 Iranian and Iranian-backed forces are helping regime troops in an offensive near Aleppo.

Obama said Iran was "just doing more of what they have been doing for the last five years, as is Russia."

"Their basic theory on how to solve Syria has not worked and will not work."

"Their preference originally was -- we will simply send arms and money to Assad and he will be able to clamp down on dissent, and when that didn't work, they directed Hezbollah to come in and prop them up and sent in some of their own military advisers, and that did not work," he said.

"Now the Russians have come in and Iran is going to send more people in, but it's also not going to work because they are trying to support a regime that in the eyes of the overwhelming majority of the Syrian people is not legitimate."