"The Americans asked us to negotiate directly with them in Montreux," Walid Moallem told Syrian state news agency SANA on the plane home after attending 10 days of peace talks in the Swiss cities of Montreux and Geneva.
"But we refused to do so before Secretary of State John Kerry apologized for what he said at the conference," Moallem added.
In his opening remarks at the conference, Kerry said Syria's President Bashar al-Assad "will not be part of" any transitional government.
Moallem also dismissed the "coalition of the so-called 'opposition'" in his remarks on Saturday.
"If they do not abandon their illusions, they will get a rude shock because we are a country of institutions and a constitution and we have a president of the republic," SANA quoted him as saying.
Moallem said it was "a stain" on the opposition that they refused to sign a declaration condemning "terrorism" in the country.
The so-called Geneva II talks between Syria's government and foreign-backed opposition kicked off on January 22, with the participation of dozens of nations.
The Geneva negotiations ended Friday with no concrete results, but the UN said that the sides to the conflict in Syria agreed to meet again on February 10.
RA/MB