A fresh push is under way to resolve Syria's four-year conflict, leading to speculation Mr Assad could be forced out to reach a settlement.
But Mr Assad said Russia and Iran did not abandon their friends.
Meanwhile France has said that that the "neutralisation" of the Syrian leader was essential to ending the crisis.
French President Francois Hollande said: "We must reduce the terrorist influence without maintaining Assad. The two are bound up together."
Iran and Russia though have maintained he needs to be part of a political solution.
The flurry of diplomatic activity on Syria has followed the recent nuclear deal reached between Iran and world powers.
But Mr Assad, speaking to Al-Manar, a Lebanese TV station run by his Hezbollah allies, said there was no imminent breakthrough in sight.
He said a solution was only possible if the outside world stopped supporting "terrorism", a term he has used to describe both opposition activists and organised jihadist groups.
The BBC Beirut correspondent, Jim Muir, says the positions spelt out by Mr Assad remain unchanged, despite the dire situation his forces face on the ground.
Syria's conflict began with anti-government demonstrations in 2011, but morphed into a bloody multi-party conflict that has left more than 250,000 dead.
The UN's envoy to the Syrian crisis, Staffan de Mistura, has proposed a series of consultations between key parties as a means towards formal peace talks.
But in his interview Mr Assad called the UN envoy biased.
The Syrian President, Bashar al-Assad, has said he is confident he has the continuing support of key allies Iran and Russia.