Washington is considering additional sanctions against Iran, a senior U.S. administration official has said.

The United States intends to follow through with new sanctions around the first anniversary of the U.S. withdrawal from a landmark international nuclear deal, the official, who was speaking on condition of anonymity, said on April 1.

President Donald Trump announced in May that the United States was pulling out of the 2015 deal meant to curb Tehran's nuclear program and ordered that sanctions be imposed again on Iran. The sanctions target Iran's energy, shipbuilding, shipping, and financial sectors.

"We just want a continued chilling effect," the official said. "We want businesses to continue to think doing business with Iran is a terrible idea at this point."

The 2015 pact, agreed by the United States, France, Britain, Germany, Russia, China, and Iran, sought to prevent Iran from developing nuclear weapons in return for the removal of sanctions that had crippled its economy.

The official said Washington hoped to take the additional measures in the coming weeks.

The Trump administration has pressed hard against what it calls Tehran's “malign” activities including alleged support for extremist violence in the Middle East, testing of ballistic and nuclear weapons, and support for Syrian President Bashar al-Assad.

Meanwhile, Iran said April 1 that U.S. sanctions were impeding aid workers from sending helicopters to flood-hit regions of the country because of the poor state of the national helicopter fleet.

Iran has announced a state of an emergency in southern regions threatened by flooding after heavy rains that have killed more than 45 people.

Foreign Minister Mohammad Javad Zarif tweeted that U.S. sanctions were "impeding aid efforts by #IranianRedCrescent to all communities devastated by unprecedented floods."

"Blocked equipment includes relief choppers: This isn't just economic warfare; it's economic TERRORISM," Zarif said.

With reporting by Reuters and dpa