Hillary Clinton, the US Secretary of State, has accused Russia of supplying attack helicopters to the Syrian government led by Bashar al-Assad.
Russia's foreign minister Sergei Lavrov says his country is not providing Syria with anything that could be used against peaceful demonstrators.
"People are pushing [Barack] Obama to be [former president] [George] Bush, which is to go in alone, ignore the UN, ignore the Russians and Chinese and to take responsibility for Syria…the entire world has shied away, they want America to do what they did in Iraq or Afghanistan."
- Joshua Landis, a Middle East Studies professor
But it turns out that Clinton was not referring to new shipments by Russia. A senior defence department official told The New York Times that Clinton was "putting a spin on it to put the Russians in a difficult position".
In Syria itself, the UN's peacekeeping chief Herve Ladsous says the conflict has escalated into a full-scale civil war.
A peace plan brokered by Kofi Annan, a former UN chief, has all but failed despite having the nominal support of all parties including the US and Russia, both of whom have differing opinions on Syria's future.
The US has repeatedly called on al-Assad to step down and wants the international community to unite with one voice calling for regime change.
Russia agrees with the UN envoy that a regional grouping should be formed to put pressure on all sides of the conflict to stop the violence.
And as part of that, Iran, which retains influence over al-Assad's regime, would be involved but that is something the US finds unacceptable.
"Why is it we always seem to find ourselves allied with 'democratic' forces that include some jihadist elements, that I find very disturbing…I know there are some concerns in Russia about, for example, the fate of Christians in Syria."
- James Jatras, a former US diplomat
Russian leaders have rejected international military intervention and despite increasingly bellicose language, the US and its European allies are not keen on the idea either.
As for the Syrian opposition, some question whether the strong words from Washington and Moscow have anything to do with their struggle for democracy.
Adip Shishakli, a member of the Syrian National Council, was quoted as saying: "What Ms [Hillary] Clinton stated yesterday it's not new to us. Russia has been providing all kind of military equipment to the Syrian regime. This is not yesterday, this is not last year, this has been going on for years and years. So this is nothing new to us. I think that her reaction yesterday is totally political."
Inside Story Americas asks: Do either the US or Russia have a plan that would actually improve the situation in Syria? And how are each country's regional interests influencing their positions in the matter?
To discuss this with presenter Shihab Rattansi are guests: Joshua Landis, the director for Middle East Studies at the University of Oklahoma; Michele Dunne, a former specialist on Middle East Affairs to the White House; and James Jatras, a former US diplomat and a senior fellow at the American University in Moscow.
"The fact is, civilians are being massacred in Syria by their government and I do think the US feels the heat of that, it's not only that the US wants to strike a blow at Iran and that's why it is saying that the government of Bashar al-Assad could go."
Michele Dunne, a former White House official
KOFI ANNAN'S SIX-POINT SYRIA PLAN:
- Work with the UN envoy to create a Syrian-led process to address the concerns of the Syrian people and commit to an interlocutor
- Government and opposition troops to stop fighting and allow the UN to supervise the cessation of violence
- Implement a daily two-hour humanitarian pause to secure provision of humanitarian assistance
- Release arbitrarily detained people and provide access to and information about people detained
- Ensure freedom of movement for journalists and a non-discriminatory visa policy for them
- Respect freedom of association and the right to demonstrate peacefully