Trump orders additional air defense troops to Saudi Arabia "The United States does not seek conflict with Iran," Esper said.

President Donald Trump has approved a "modest deployment" of American troops and air and missile defense systems to Saudi Arabia in the aftermath of last weekend's attack on Saudi oil facilities that the U.S. has blamed on Iran, Defense Secretary Mark Esper announced at a hastily called Pentagon press conference on Friday night.

Trump's decision to deploy troops to Saudi Arabia followed a high-level national security meeting at the White House on Friday afternoon.

Esper said Saudi Arabia and the United Arab Emirates had requested international support to help protect critical infrastructure. In addition to the troops and weapons systems headed to Saudi Arabia, the U.S. also will expedite weapons purchases.

"In response to the Kingdoms' request," Esper said, "the president has approved the deployment of U.S.forces, which will be defensive in nature and primarily focused on air and missile defense."

The exact number of weapons systems and troops remains to be determined and may not be finalized until early next week, said Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff, who added that the size of the force would not be in the "thousands."

Esper called last weekend's attack a "dramatic escalation of Iranian aggression" and said all indications are that Iran was responsible.

"The United States does not seek conflict with Iran," said Esper, who added that the U.S. has military options should they become necessary.

Esper called the deployment of U.S. troops and air defense equipment a "first step" and called on other members of the international community to "stand up" and consider also providing additional defensive support. Dunford said the deployment would enhance Saudi Arabia's air missile defense systems.

The U.S. currently has a Patriot missile defense battalion with about 600 troops at Prince Sultan air base outside of Riyadh that was deployed in late May after a series of commercial tankers were attacked by Iran in the Persian Gulf.

With a 100-mile range, that air defense system was not capable of defending the attack on the facilities approximately 200 miles away that briefly disrupted 5% of the world's oil supply. Saudi Patriot air defense systems are deployed to the southern part of the country to defend against ballistic missile attacks by the Houthi rebels in Yemen, not oriented toward Iranian provocations from the north.

Earlier on Friday, Trump announced sanctions on Iran's national bank he described as "the highest sanctions ever imposed on a country."

"This will mean no more funds going to the [Islamic Revolutionary Guard Corps] to fund terror. This is on top of our oil sanctions and our financial institution sanctions," said Treasury Secretary Steve Mnuchin. "This is very big. We've now cut off all source of funds to Iran."

On Friday afternoon, the president convened a meeting of his senior advisers to consider options to retaliate against Iran for the strike. Those options reportedly included everything from the deployment of more U.S. forces to help defend the Saudis, no additional forces, a limited proportional airstrike, no military action or striking a broader range of targets.

In earlier national security meetings, officials had decided to let the Saudis take the lead.

The U.S. is "always prepared" to use a military option against Iran, the president said in the Oval Office on Friday ahead of the meeting.