The United States targeted Irans petrochemical industry in new sanctions imposed on Friday, including the countrys largest petrochemical holding group over its financial support for the Revolutionary Guard Corps (IRGC), the Treasury Department said. The new sanctions come as Washington keeps up pressure against Iran over its ballistic missile program and for waging proxy wars in other Middle Eastern countries. The sanctions target PGPIC for providing financial support the economic arm of the IRGC. Treasury also designated the holding groups network of 39 subsidiary petrochemical companies and foreign-based sales agents. PGPIC and its subsidiaries hold 40 percent of Iran’s petrochemical production capacity and are responsible for 50 percent of Iran’s total petrochemical exports, it said. "By targeting this network we intend to deny funding to key elements of Irans petrochemical sector that provide support to the IRGC," Treasury Secretary Steven Mnuchin said in a statement. The Treasury statement said Irans oil ministry last year awarded the IRGC’s Khatam al-Anbiya, the IRGCs economic and engineering arm, 10 projects in oil and petrochemical industries worth $22 billion, four times the official budget of the IRGC. The United States in April officially designated the IRGC as a foreign terrorist organization. US law already punished US persons who deal with the IRGC with up to 20 years in prison because of the group’s designation under the Specially Designated Global Terrorist list, a different sanctions program. Meanwhile, Iran in a letter to the United Nations made public on Friday, complained that the re-imposition of US sanctions violates not just the nuclear deal but also UN Security Council resolution that enshrined it. "The United States unilateral nuclear as well as economic sanctions in defiance of Security Council Resolution 2231 and the Joint Comprehensive Plan of Action have reached an unprecedented level during the past few months," Irans ambassador to the United Nations said in the letter, which was dated May 23. "The United States shall bear full responsibility for the consequences of those wrongful acts," Ambassador Majid Takht Ravanchi. "The international community should uphold its responsibilities under the Charter of the United Nations and consider and react proportionately to the unlawful conduct of the United States that has endangered international peace and security."