DUBAI - Iran will not cooperate with the United States on the “fight against terrorists in Syria”, a top adviser to Supreme Leader Ayatollah Ali Khamenei was quoted as saying by state media on Wednesday.

“Iran will not cooperate directly or indirectly with the United States,” Ali Akbar Velayati was quoted as saying on Press TV after a meeting with Syrian Deputy Foreign Minister Faisal Mekdad in Tehran.

“Iran will not accept any initiative regarding Syria without consultation with the country’s government and people,” Press TV also quoted Velayati as saying. In a meeting with Mekdad on Wednesday, Iran’s foreign minister reiterated Tehran’s position that it believed the Syrian crisis only had a political solution.

“We believe only the Syrian people should decide about their future and others can only facilitate this political process to resolve the crisis,” Mohammad Javad Zarif was quoted as saying by Fars news agency. World and regional powers including rivals Iran and Saudi Arabia met in Vienna this month to discuss a political solution to Syria’s civil war but failed to reach a consensus on the future of President Bashar al-Assad.

Iran backs Assad in the war while Saudi Arabia supports rebels seeking to oust him. It was the first time Tehran and Riyadh were at the same table to tackle a war that has evolved into a wider proxy struggle for regional dominance between Russia and Iran on Assad’s side and Turkey, U.S.-allied Gulf Arab states and Western powers who support rebels to varying degrees.

Eighty-five to 90 percent of Russian strikes in Syria have hit the moderate Syrian opposition, the top U.S. diplomat for the Middle East told a congressional committee on Wednesday. Russia boosted its military support for President Bashar al-Assad’s fight against rebels in the four-and-a-half year Syrian civil war, beginning air strikes last month that it said would also target the IS.

“Moscow has cynically tried to claim that its strikes are focused on terrorists, but so far 85 to 90 percent of Syrian strikes have hit the moderate Syrian opposition,” Assistant Secretary of State for Near Eastern Affairs Anne Patterson told lawmakers. Testifying with her, the top U.S. diplomat for Europe, Victoria Nuland, said Russia had also begun to deploy ground assets such as artillery to areas Assad forces have lost to the moderate opposition, including near the cities of Hama and Homs.

“Russia is fielding its own artillery and other ground assets around Hama and Homs, greatly increasing Russia’s own soldiers’ vulnerability to counterattack,” Nuland, assistant secretary of state for European and Eurasian Affairs, said. Patterson also told the House hearing that President Barack Obama is considering additional ways to “intensify” the campaign against the Islamic State, which has seized swaths of territory in Syria and Iraq.

“The president is looking at a number of other efforts to intensify our efforts in this battle,” she said. The Obama administration last week announced it would send fewer than 50 special operations forces into Syria in an advise and assist capacity, weeks after Russia escalated its involvement in the conflict with its own air strikes.