Washington imposed sanctions on Iran's main agency in charge of broadcasting on Wednesday for helping the government censor Western reports, and targeted Iran's oil earnings in an effort to prevent funds being used on its disputed atomic program.
The West believes Iran is seeking to develop nuclear weapons but Iran maintains its nuclear program is entirely peaceful.
"The new round of sanctions ... are designed to put pressure on the nation and to create a gap between the (Iranian) nation and government," Foreign Ministry spokesman Ramin Mehmanparast was quoted as saying by the semi-official Fars news agency.
"In the remaining time to the (presidential) election, they want to create tension, crisis and instability in the country by imposing great pressure," he added.
Ayatollah Ali Khamenei, Iran's highest authority, on Thursday rebuffed a U.S. offer of direct talks, saying Iran would not be intimidated by pressure or the threat of military action.
(Reporting by Zahra Hosseinian; Editing by Jon Boyle)