The U.S. Secret Service said Wednesday it had intercepted suspect packages, identified as potential explosive devices, sent to the homes of former president Barack Obama and former secretary of state Hillary Clinton.

The Secret Service said it recovered a single package addressed to Clinton in Westchester, a suburb north of Manhattan on Tuesday, and a second package addressed to the Obama residence in Washington on Wednesday.

An official says investigators believe the explosives are linked to one found Monday at the compound of progressive billionaire George Soros. The Associated Press’ source wasn’t authorized to publicly discuss an ongoing investigation and spoke on condition of anonymity.

“Secret Service recovered a single package addressed to Former First Lady Hillary Clinton in Westchester County, New York. Early this morning, October 24, 2018, a second package addressed to the residence of Former President Barack Obama was intercepted by Secret Service personnel in Washington, DC,” the Secret Service said in a statement. “The packages were immediately identified during routine mail screening procedures as potential explosive devices and were appropriately handled as such. Both packages were intercepted prior to being delivered to their intended location. The protectees did not receive the packages nor were they at risk of receiving them.”

CNN crime correspondent Shimon Prokupecz reports law enforcement officials are concerned additional suspicious packages may have been sent to others.

This story is developing.