A highly radioactive material used to treat cancer is back on U.S. soil after American officials removed it from Guatemala over concerns it could be stolen and used to create a “dirty bomb.” The cobalt-60 source had been housed inside a disused medical radiation device before U.S. and Guatemalan teams removed the radioactive component and transported it to secure storage in the United States. The U.S. National Nuclear...

The Trump administration spent months insisting Iran did not control passage through the Strait of Hormuz. But after Iran and Oman unveiled a proposed framework that Tehran says would exclude military vessels if finalized, the White House would not say whether President Donald Trump would accept any restriction on U.S. warships under the arrangement. U.S. Central Command, meanwhile, rejected Iran’s underlying claim of authority. “Iran does not control...

Marine One’s crew made repeated but unsuccessful attempts to notify Reagan National Airport that President Donald Trump’s helicopter was preparing to depart Aug. 4 before it flew near a commercial passenger jet, according to a preliminary federal report released Thursday. The National Transportation Safety Board’s preliminary report said the crew’s first call to Reagan National’s helicopter-control frequency before departing from the Ellipse was not received. A second transmission...