The United States on Thursday displayed pieces of what it said were Iranian weapons deployed to militants in Yemen and Afghanistan, a tactic by President Donald Trump's administration to pressure Tehran to curb its regional activities.

The second presentation of Iranian weapons by the Pentagon, many of which were handed over by Saudi Arabia, coincides with growing concern in Congress over U.S. military support for the Saudi-led coalition in Yemen's civil war, which has led to a deep humanitarian crisis.

Members of Congress have escalated their opposition to Saudi Arabia after the Oct. 2 killing of Saudi journalist Jamal Khashoggi in its Istanbul consulate. Despite administration pleas to stick with the Saudis and thereby counter Iran, the Senate voted on Wednesday to advance a resolution to end military support for the Saudis in Yemen.