US Secretary of State Marco Rubio spoke with Lebanese President Joseph Aoun on the confiscation of hundreds of kilograms of explosives from Hezbollah, a State Department official said on Thursday.

Rubio urged Aoun to hold accountable those who ordered, financed, and directed the shipment, and "underscored that returning explosives to (Hezbollah) should be out of the question," the State Department official said.

This is a developing story.