A senior official said the US only pretends to fight terrorists.
Secretary of Supreme National Security Council Ali Shamkhani made the statement in an interview with the state TV, IRNA reported.
On US-led coalition efforts to fight the Islamic State militants in Iraq and Syria, the official said, "Indeed, the IS is a tool of the West to help pursue its Middle East policies."
Shamkhani pointed to the fact that while it was launched more than a year ago, the US-led coalition could not deal a decisive blow to the militant group, stressing that the US, equipped with drones and satellites, is able to hurt the IS, but despite conducting 130 sorties daily, the US-led airstrikes only hit 12 targets.
"The US knows how IS transports Iraqi oil using tankers, whose number often reaches 100 per day, but never attacks these tankers because it will harm the revenues of IS and limit its power," he said.
Shamkhani noted that "Iran's policy toward terrorism is not similar to that of the US", as it has been seriously assisting the Iraqi and Syrian governments' fight against IS militants since they landed in the region.
On efforts to fight regional terrorism, Shamkhani referred to the crisis in Syria and said Iran's contribution to the fight against extremists is limited to advisory roles and it will not participate in ground operations.
The SNSC secretary said the collapse of governmental structures in regional states like Syria and Iraq would have a major impact on Iran's national security, for which reason Iranian assistance to defeat terrorists is necessary.
--"Explicit" Response
"Iran would react to any violations of the nuclear deal, reached between Iran and world powers in Vienna in July, in an explicit manner," he said.
In case of a breach of obligations, possibly by the US, "Iran will soon return to desired point," he said, meaning that restrictions placed on the nuclear program will be removed and Iran will take the program back to where it was before the deal.
On the implementation of the Joint Comprehensive Plan of Action, as the deal is formally called, Shamkhani said Iran is waiting for the Board of Governors of the International Atomic Energy Agency to announce the closure of Iran's nuclear file.
"The implementation phase of the deal is on schedule," he said, adding that preparations for dismantling centrifuges in the nuclear facilities have been made, but not a single centrifuge has been removed yet.
Pointing to opposition to the implementation of JCPOA in some domestic quarters on the grounds that it will negatively affect Iran's nuclear achievements, the SNSC secretary said Iran will move toward developing an advanced, peaceful nuclear capability.
"Iran should try to adopt a smart approach toward the implementation of the deal, not to refuse it as a whole," he said.
