"The events in Syria are its internal affair and there is no justification for any foreign intervention as it can only create many problems," Mehmanparast said during his weekly press briefing.
"Western leaders, especially Americans, are used to interfering in the internal affairs of countries and using any pretext to march with their military forces and occupy the country," he added.
Mehmanparast also warned that any intervention by Washington, Tehran's archfoe, will only stoke "public hatred" of the United States in the region.
Syria has repeatedly said it is battling "armed terrorist gangs" -- a claim denied by rights groups who say a crackdown by the regime on a popular revolt has killed 1,827 civilians since mid-March, while 416 security forces also died.
The United States is leading Western nations in mounting pressure on Damascus, saying that President Bashar al-Assad has lost his legitimacy and that his people "would be better off without him." Several regional countries, including Turkey, Saudi Arabia, Kuwait, Bahrain and Jordan, have also denounced the crackdown on Syrian protesters.
Mehmanparast called on neighbouring countries to assist in "bringing stability to the region and resolving, through appropriate channels, the problems between the Syrian government and people who have claims."