The US government on Thursday imposed sanctions on Iran’s construction sector and the transfer of four materials related to Tehran’s nuclear or military programmes.

The US State Department said in a statement that Iran’s construction sector was blacklisted as it was “controlled directly or indirectly” by Iran’s Islamic Revolution Guards Corps (IRGC), which was designated by the US as a terrorist organization in April, Xinhua news agency reported.

The decisions announced by State Department reflect an effort to increase economic pressure on Iran by putting wider swathes of its economy under sanctions, while also leaving a door open to diplomacy by allowing work to proceed at Iranian nuclear facilities that make it harder for Iran to develop a nuclear weapon.

The US also slapped sanctions on the trade of four materials with Iran, which Washington claimed were used in connection with Tehran’s nuclear, military or ballistic missile programmes, said the statement.

The latest sanctions are part of the US campaign to maximize economic pressure on Iran, the Department added.

Secretary of State Mike Pompeo had determined Iran’s construction sector was controlled directly or indirectly by Iran’s Islamic Revolutionary Guard Corps (IRGC), which the United States has branded a foreign terrorist organization.

In a second determination, he identified four “strategic materials” as being used in connection with nuclear, military, or ballistic missile programs, making a trade in them subject to sanctions.

Earlier in September, the US imposed its first-ever sanctions against Iran’s space agency, accusing it of disguising a missile program.

The US also warned the “international scientific community that collaborating with Iran on space launch vehicles could contribute to its ballistic missile program.”

In response to the US, Iran had said that its space program is aimed at building rockets to launch telecommunications satellites. Iran has fired two such satellites into orbit since 2013. But three other attempts this year have failed, including one rocket that blew up on the launchpad.

Iranian officials have stressed that for any talks with the US, Washington should return to Tehran’s nuclear deal from which it withdrew in 2018 and implement its obligation under the accord.

Following the exit from the Iran nuclear deal, President Trump’s administration has kept piling up pressure on Iran through a series of sanctions and designations, which have been strongly opposed and criticized by Tehran.

(With inputs from agency)