By Pooya Stone

The United States State Department announced Thursday that it has imposed sanctions on Iran's construction sector and the transfer of four materials related to the country's nuclear or military programs.

The State Department said in a statement that Iran's construction sector was blacklisted as it is "controlled directly or indirectly" by Iran's Islamic Revolution Guards Corps (IRGC), which was designated by America as a terrorist organization in April.

The United States also slapped sanctions on the trade of four materials with Iran, which Washington claimed are used in connection with Iran's nuclear, military or ballistic missile programs, said the statement.

Because of this connection, the U.S has barred the sale, supply or transfer of raw and semi-finished metals, graphite, coal, and industrial software to or from Iran for use with its construction sector, the State Department said in a statement.

The latest sanctions are part of the U.S. campaign to maximize economic pressure on Iran, it said.

State Department spokeswoman Morgan Ortagus said in a statement: "With these determinations, the United States will have additional authorities to prevent Iran from acquiring strategic materials for the IRGC, its construction sector, and its proliferation programs."

Ortagus said the move "will help preserve oversight of Iran's civil nuclear program, reduce proliferation risks, constrain Iran's ability to shorten its 'breakout time' to a nuclear weapon, and prevent the regime from reconstituting sites for proliferation-sensitive purposes."

Meanwhile, it was reported on Thursday that the U.S. State Department had extended sanctions waivers that permit foreign companies to work with Iran's civilian nuclear program without facing U.S. punishment. The waivers, which were due to expire on Tuesday, were extended for another 90 days.

The measures are part of the United State's maximum pressure campaign to force Iran back into negotiations over its nuclear program following President Donald Trump pulling out of a landmark, a multination pact with Iran aimed at restricting its nuclear program in May 2018.