President Donald Trump on Wednesday pledged to "substantially increase" sanctions on Iran as tensions in the Middle East continue to rise following an attack on a Saudi oil field.

"I have just instructed the Secretary of the Treasury to substantially increase Sanctions on the country of Iran!" Trump tweeted.

Trump's tweet came as U.S. Secretary of State Mike Pompeo was headed to Saudi Arabia to meet with Crown Prince Mohammed bin Salman to discuss the recent attack on the kingdom's oil facilities, an action American officials believe originated from Iranian territory.

Iranian President Hassan Rouhani said Saudi Arabia should see the attack on its oil facilities as a warning to end the war in Yemen, while insisting the attack came from Yemeni forces.

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