Tensions between Syria and Saudi Arabia intensified Thursday ahead of talks with Iran and the U.S. on a solution to the Syrian war.

Syria criticized Saudi Arabia on pro-state Syrian al-Ikhbariya TV, saying it is not qualified to play a "productive" role in resolving the Syrian War because it is shedding the blood of Muslims and Arabs there, in Yemen and in Iraq.

The information minister’s comments come one day after Saudi foreign minister Adel Jubeir said there is no role for Syrian President Bashar al-Assad in the political transition.

Nearly 20 nations have signaled that they are attending Thursday’s talks in Vienna, including the United States and bitter regional rivals Iran and Saudi Arabia. Secretary of State John Kerry has already arrived in Vienna and Iranian Foreign Minister Mohammad Javad Zarif is expected to land later Thursday.

Progress will be elusive. Backed by Washington, the Saudis want to topple Assad, while Iran and Moscow support him.

Also Thursday, Doctors Without Borders reported an escalation in deaths from airstrike attacks on hospitals in Syria in the last month -- roughly the same period Russia began its air campaign in the war-torn country.

The international medical charity said 35 Syrian patients and medical staff have died and 72 have been wounded in the attacks in northern Syria's provinces of Aleppo and Idlib and the central provinces of Hama.

These are also provinces where Russian airstrikes have largely been taking place since Sept. 30. Syrian government jets have also continued their attacks in the meantime.

The aid group says 12 hospitals have been targeted in attacks, including six it supports. The attacks have caused five hospitals to shut down.

Earlier, Syria's exiled opposition rejected any role for President Bashar Assad in the political transition "even for one day.”

Syrian National Coalition member Bassam Abdullah also warned against wasting time on political initiatives like Vienna, saying they are attempts to allow the military time to regain territories from rebels.

But Russia's Foreign Ministry insists the international talks should help launch an inter-Syrian political dialogue and achieve political settlement.

Ministry spokeswoman Maria Zakharova told reporters Thursday that Moscow is satisfied to see that Iran and Egypt have been invited to join the talks among other participants.

She said using the potential of all regional players is essential for the success of the talks and unilateral approaches won't work.

Zakharova also rejected allegations that Russia's air campaign in Syria has caused civilian casualties as lies, reaffirming that the Russian warplanes only target terrorist infrastructure.

A first round of diplomatic talks last week did not include Iran. The talks formally begin Friday but Kerry is expected to meet some other participants later Thursday.

The Associated Press contributed to this report.