U.S. oil facilities in the Middle East are considered a likely target of Iranian retaliation for the killing of Iran's top military leader — and are tightening security in the region, The Wall Street Journal reported.

A call by the U.S. Embassy in Baghdad for all U.S. citizens to leave Iraq is expected to affect staffing at Exxon Mobil Corp., which operates facilities in the Iraq's volatile southern region. The company will maintain production with local workers, analysts told the Journal.

BP declined to comment on security or staffing, and Chevron Crop. in Iraqi Kurdistan would only tell the Journal that the safety of its staff and facilities is a priority.

Even before the airstrike in Iraq that killed Gen. Qassem Soleimani, American companies had been taking steps to secure facilities and protect workers in Iraq amid rising tensions, the Journal reported.

Following the September attack on Saudi Arabia oil facilities, U.S. preparations include at least one scenario in which Iran launches missile strikes on the Saudi oil terminal of Ras Tanura, the Journal reported.

The United Arab Emirates' energy assets and its trading hub of Dubai are also vulnerable, with one unnamed source familiar with the Islamic Revolutionary Guard Corps telling the Journal: Dubai "will not be safe anymore."

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