The following is the May 16, 2019 Congressional Research Service report, U.S.-Iran Tensions Escalate.

From the report

U.S.-Iran tensions have escalated in recent weeks as the Trump Administration has taken several significant steps in its campaign of applying “maximum pressure” on Iran, and Iranian leaders have announced responses. U.S. steps have included designating Iran’s Islamic Revolutionary Guard Corps (IRGC) as a Foreign Terrorist Organization (FTO), reimposing sanctions on any country that buys Iranian oil, ending sanctions waivers for some assistance to the permitted aspects of Iran’s nuclear program, and imposing new sanctions on transactions in some Iranian commodities. U.S. officials state that reports about potential Iran-linked threats to U.S. forces and interests prompted the Administration to send additional military assets to the region. Yet, press reports on May 16 indicate that President Donald Trump prefers a diplomatic solution to continued escalation that could lead to conflict.

Members of Congress have been requesting additional information from the Administration about the uptick in U.S.-Iran tensions. Congress might consider the broader Administration’s Iran policy or the potential for use of force against Iran.

Recent Administration Steps to Pressure Iran

Recent Administration efforts to increase pressure on Iran’s economy and government include:

On April 8, 2019, the Administration designated the IRGC as a Foreign Terrorist Organization (FTO). Iran’s parliament responded by enacting legislation declaring U.S. Central Command (CENTCOM) and related forces in the Middle East to be terrorists.

As of May 2, 2019, the Administration ended a U.S. sanctions exception for the purchase of Iranian oil to try to drive Iran’s oil exports to “zero.”

On May 3, 2019, the Administration ended waivers under the Iran Freedom and Counter-Proliferation Act (IFCA, P.L. 112-239) that allow countries to help remove Iranian heavy water and low-enriched uranium that exceed JCPOA stockpile limits.

On May 5, 2019, citing reports that Iran might be preparing its allies to attack U.S. personnel or installations, National Security Adviser John Bolton announced that the United States was accelerating the previously planned deployment of the U.S.S. Abraham Lincoln Carrier Strike Group to the region and sending a bomber task force to the Persian Gulf region.

On May 8, the President issued Executive Order 13871, blocking the U.S.-based property of persons and entities determined by the Administration to have conducted significant transactions with Iran’s iron, steel, aluminum, or copper sectors. These commodities account for about 10% of Iran’s exports, but the exports primarily go to regional companies that might not be easily penalized by U.S. sanctions.

Download the document here.