(AP) -- Russia's U.N. ambassador said Wednesday the United States has not made a case for new Security Council action against Iran with parts of missiles the Trump administration claims were supplied by Tehran to Yemen's Houthi fighters.

Ambassador Vassily Nebenzia said in comments released by Russia's U.N. Mission that it was unclear whether missile parts that council members were taken to see in Washington on Monday were Iranian or violated a 2015 arms embargo on Yemen.

The Trump administration maintains that fragments from missiles recovered in Saudi Arabia after being launched from Yemen by the Houthis contain markings proving they were Iranian-made, though some security experts have questioned whether the evidence is foolproof.

Nebenzia said Iran "is vehemently denying it is supplying anything to Yemen."

The Arab world's poorest country, Yemen is engulfed in a war that has killed more than 10,000 civilians, displaced 2 million people, and left 7 million on the brink of famine.

Houthi Shiite fighters and forces allied to former President Ali Abdullah Saleh swept into the capital, Sanaa, in 2014 and control much of northern Yemen.

They have been locked in a bloody stalemate for most of the last three years with a Saudi-led coalition, backed by the United States, which supports Yemen's former President Abed Rabbo Mansour Hadi. It launched an air campaign against the fighters in March 2015.

"Yemen hosts a pile of weapons from the old days," Nebenzia said, with "many countries competing to supply weapons to Yemen during the time of President Saleh. So I cannot give you anything conclusive. I am not an expert to judge."

Saleh, who was president in 1990-2012, was killed by the Houthis in December when he was about to switch support to the coalition.

U.S. Ambassador Nikki Haley has raised the possibility of new U.N. action against Iran.

Nebenzia said he has only heard "vague talk of action" and would wait to see what is proposed.

Asked whether a case had been made for new action at the U.N. against Iran, he replied, "No."

Kazakhstan's U.N. ambassador, Kairat Umarov, the current Security Council president, told reporters Wednesday that he also had questions after viewing the missile fragments.

"Unfortunately, we don't know at this point in time how this weaponry was delivered to Yemen," he said, adding that for some time there have been different governments as well as "commercial people who like to send weaponry."