President Bashar al-Assad said Russian leadership never discussed a political transition with him, while he heaped praise on Moscow, and derision on Washington, over their bombing campaigns in the country.
In an interview with NBC television to be broadcast Thursday, al-Assad also denounced Turkey, Qatar and Saudi Arabia for supporting what he described as "terrorist groups" in Syria - a reference to the armed opposition, which includes hardline factions, such as al-Qaeda.
"Russian politics is not based on making deals, it is based on values. The American politics is based on making deals regardless of values," al-Assad charged, saying Damascus and Moscow shared a "common interest" in fighting terrorism, which can strike anywhere.
Whether al-Assad will remain as president of Syria has been a key hurdle in talks between the government and the opposition, and Russia's exact position for the long-term has been unclear.
He insisted to the US broadcaster that President Vladimir Putin "didn’t ask for anything" in exchange for boosting support last year to Syria. He also noted that China and Iran "stood beside" his government.
"Definitely, the Russian support of the Syrian army has tipped the scales against the terrorists," said al-Assad, while denouncing US airstrikes against Islamic State as "illegal" and as the campaign was started without Damascus' permission.
"Since the beginning of the American airstrikes the terrorism has been expanding and prevailing. It only shrank when the Russians intervened. So, this is reality," said al-Assad. “The United States does not have the will to defeat the terrorists.”
The embattled Syrian leader also insisted his troops did not target slain US journalist Marie Colvin, who was killed in 2012. Her family this week launched a law suit against the Syrian government.
Throughout the interview, al-Assad insisted he would only stay in power if the Syrian people wanted this.
The uprising against al-Assad - who took over from his father in 2000 - began in 2011, with people taking to the streets to peacefully protest, demanding more rights and his resignation.
A severe crackdown devolved into a civil war which has left at least a quarter of a million people dead and displaced 12 million Syrians. Entire cities have been destroyed.