[10] Unable to import weapon systems from abroad due to international and U.S. sanctions, and suffering from an increasingly aging air force fleet, Iran has invested considerable funds into an ambitious ballistic and cruise missile program for mid-range strike capability,[11] and has manufactured different types of arms and munitions, including tanks, armoured vehicles and drones, as well as various naval assets and aerial defense systems.

[16][17] The Iranian drone program has also raised concerns across the Middle East and much of the Western world, especially with proliferation among Iranian-allied forces in the Middle East, as well as exports to countries hostile to the U.S.[18] According to U.S. Central Command chief Gen. Kenneth McKenzie, the U.S. is "for the first time since the Korean War operating without complete air superiority" due to threats posed by Iranian drones.

Following the Iranian revolution in 1979, deteriorating relations with the U.S. resulted in international sanctions led by the US, including an arms embargo being imposed on Iran.

From 1987, the United States Central Command sought to stop Iranian mine-laying vessels from blocking the international sea lanes through the Persian Gulf in Operation Prime Chance.

Simultaneously, the Iranian armed forces had to learn to maintain and keep operational, their large stocks of US-built equipment and weaponry, without outside help, due to the American-led sanctions.

However, Iran was able to obtain limited amounts of American-made armaments, when it was able to buy American spare parts and weaponry for its armed forces, during the Iran–Contra affair.

Between 1989 and 1992, Iran spent $10 billion on arms, some of which were designed to prevent other states' naval vessels from accessing the sea, including marines and long-range Soviet planes capable of attacking aircraft carriers.

In 2004, Iranian armed forces took Royal Navy personnel prisoner, on the Shatt al-Arab (Arvand Rud in Persian) river, between Iran and Iraq.

In 2007, Iranian Revolutionary Guard forces also took prisoner Royal Navy personnel when a boarding party from HMS Cornwall was seized in the waters between Iran and Iraq, in the Persian Gulf.

According to Juan Cole, Iran has never launched an "aggressive war" in modern history, and its leadership adheres to a doctrine of "no first strike".

[23] On 4 December 2011, an American RQ-170 Sentinel unmanned aerial vehicle (UAV) was captured by Iranian forces near the city of Kashmar in northeastern Iran.

In 2012, it was announced that Iran's Quds Force is operating inside Syria providing the government of Bashar al-Assad with intelligence and direction against rebel opposition.

In November 2015, Iranian special forces assisted in the rescue of a Russian pilot that was shot down by Turkey, over Syria.

[26] In 2016, Revolutionary Guard forces captured US Navy personnel when their boats entered Iranian territorial waters off the coast of Farsi Island in the Persian Gulf.

In March 2021 state TV in Iran showed footage of a "missile city" armed with ballistic and cruise weapons described as "a new Revolutionary Guard base" along the Gulf coast.

[47] Since 1992, it has also produced its own tanks, armored personnel carriers, radar systems, guided missiles, marines, military vessels and fighter planes.

[53] In recent years, official announcements have highlighted the development of weapons such as the Fajr-3 (MIRV), Hoot, Kowsar, Fateh-110, Shahab-3 missile systems and a variety of unmanned aerial vehicles, at least one of which Israel claims has been used to spy on its territory.

These launches came after some United States-led military exercises in the Persian Gulf on October 30, 2006, meant to train for blocking the transport of weapons of mass destruction.

[65] Iran has advanced biological and genetic engineering research programs supporting an industry that produces vaccines for both domestic use and export.