REUTERS/Leah MillisWASHINGTON, April 27 (Reuters) - As Iran's oil exports rise despite U.S. sanctions over its nuclear program, senators from both parties urged President Joe Biden to enable a federal government agency to seize Iranian oil and gas shipments. Senators Joni Ernst, a Republican, and Richard Blumenthal, a Democrat, said in a letter to Biden that the Department of Homeland Security's Homeland Security Investigations (HSI) office has not been able to seize an Iranian oil shipment for more than a year. Iran says its nuclear program is for civilian purposes while the United States suspects Tehran wants to develop a nuclear bomb by enriching uranium. Iran's oil exports have reached their highest level since the reimposition of U.S. sanctions in 2018, Iranian oil minister Javad Owji said last month. Last year the U.S. tried to confiscate a cargo of Iranian oil around Greece, which prompted Tehran to seize two Greek tankers in the Gulf.

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