The United States is imposing new sanctions against 18 individuals and entities over their support for Iran's ballistic-missile program and other military-related activities.
The sanctions come one day after Washington certified that Iran is complying with the 2015 nuclear deal and will continue to receive nuclear-related sanctions relief.
"Even as we continue to work to prevent Iran from ever obtaining a nuclear weapon, we cannot look away while Iran threatens our country and our allies in ways beyond their nuclear threat," White House spokeswoman Sarah Sanders told reporters July 18.
Iran condemned the new American sanctions and responded with its own sanctions against Americans, the official news agency IRNA reported.
The U.S. Treasury Department said in a statement on July 18 that it was targeting 16 entities and individuals for "engaging in support of illicit Iranian actors or transnational criminal activity."
Those sanctioned have supported Iran's military or the Islamic Revolutionary Guards Corps (IRGC) by developing military equipment, producing and maintaining fast-attack boats, and procuring electronic components, the department said.
"This administration will continue to aggressively target Iran's malign activity, including their ongoing state support of terrorism, ballistic missile program, and human rights abuses," Treasury Secretary Steven Mnuchin was quoted as saying in the statement.
The State Department also said it was designating two Iranian organizations involved in Iran’s ballistic-missile program.
State Department spokeswoman Heather Nauert said Iran was testing and developing ballistic missiles "in direct defiance" of a UN Security Council resolution.
The new sanctions were "in response to these continued Iranian threats," she said in a July 18 statement.
The State Department called on Iran to release U.S. citizens including Baquer Namazi, Siamak Namazi, and Xiyue Wang -- whose arrest and prison sentence on espionage charges was announced by a judiciary spokesman over the weekend.
On July 17, U.S. President Donald Trump's administration certified that Iran is complying with the 2015 nuclear deal and would continue to receive nuclear-related sanctions relief.
It was the second time since Trump took office in January that the administration had certified Iranian compliance with the agreement, which Trump promised to "rip up" and called the "worst deal ever" during the election campaign in 2016.
Iran's Foreign Ministry condemned the U.S. move, which it called "the United States' worthless act of imposing illegal sanctions," IRNA reported on July 18.
Tehran "will in turn apply new sanctions against American people and entities that have acted against the Iranian people and other Muslim peoples of the region," it said.
The 2015 nuclear deal between Iran and world powers eased sanctions against Tehran in return for curbs on Tehran's nuclear program.
While certifying that Tehran has adhered to the terms of the agreement it forged with Washington and five other world powers, the administration lambasted Iran for breaching what it called "the spirit" of the deal by continuing to develop and test ballistic missiles and fast boats.
"Iran remains one of the most dangerous threats to U.S. interests and regional stability," a senior U.S. official told reporters on condition of anonymity on July 17, adding that the administration is looking at ways to try to strengthen the 2015 deal and more strictly enforce it.
Representatives of nuclear powers China, Russia, France, Britain, and the United States -- plus Germany -- are to meet in Vienna on July 21 to take stock of the 2015 deal.