"No measure against the Islamic Republic of Iran will go unanswered and we will respond proportionally to any move," Zarif told the IRIB 1 television channel late Monday .
Zarif said US claims about Iran's missile activities are unlawful, citing UN Resolution 2231 which only bans development of missiles capable of nuclear warheads.
"While Resolution 1929 banned any missile-related activities, this restraint in Resolution 2231 only includes missiles capable of carrying nuclear warheads. This is while we basically do not need such missiles," he said.
Emad ballistic missile
"“This US claim has no international ground and, as per the directive of President (Hassan Rouhani), we will continue our missile activities more than before with the aim of deterrence,” Zarif added."
Iran successfully test-fired its domestically-built Emad ballistic missile on October 11, 2015.
On Sunday, the US Department of the Treasury announced new sanctions on several individuals and firms over Iran’s missile program, a day after similar bans were officially lifted against the Islamic Republic.
The new sanctions were in response to Iran's successful test of its first guided ballistic missile, Emad, in October.
Reacting to the bans, President Hassan Rouhani ordered Iran's Defense Ministry to expedite boosting the country’s missile capabilities, PRESS TV reports
On Monday, Defense Minister Brigadier General Hossein Dehqan said Iran would unveil new homemade missiles in the near future.
“Any attempt to impose new sanctions under irrelevant pretexts is indicative of continued US hostile policy and antagonism with the Iranian nation, and a futile effort to undermine Iran’s defense might,” Dehqan said.
In recent years, Iran has made great achievements in its defense sector and attained self-sufficiency in producing essential military equipment and systems.
The Islamic Republic has repeatedly said its military might poses no threat to other countries, reiterating that its defense doctrine is based on deterrence.