Speaking in the Oval Office during a meeting with Australian Prime Minister Scott Morrison, the US president said, "We have just sanctioned the Iranian national bank."
"It’s going to hell," Trump said, referring to Iran’s economy, Sky News reported.
He said, "I think the sanctions work. The military would work. That's a very severe form of winning."
US Treasury Secretary Steven Mnuchin told reporters the bank was Tehran's last source of funds, saying, "We have now cut off all funds to Iran".
The Yemeni forces on September 14 launched drone attacks on two plants at the heart of Saudi Arabia's oil industry, including the world's biggest petroleum processing facility.
The attacks came in retaliation for the Saudi-led coalition’s continued aggression on the Arabian Peninsula country.
Since March 2015, Saudi Arabia and some of its Arab allies have been carrying out deadly airstrikes against the Houthi Ansarullah movement in an attempt to restore power to fugitive former president Abd Rabbuh Mansour Hadi, a close ally of Riyadh.
Iran has strongly denied any involvement in the attacks on the Saudi Aramco facilities, which shook global oil markets.
Tehran has warned that any strike on it by the US or the kingdom would lead to "an all-out war".