Ukraine recently struck vessels in the Caspian Sea and asserted that the ships took part in military shipments tied to Iran. Ukrainian President Volodymyr Zelensky added that Russia is extending fresh help to the Iranian government. He noted that since early July Russian satellites have actively watched Gulf states and American military sites in the area.

The Ukrainian claims highlight deeper ties between Moscow and Tehran. Many of these links were already familiar to observers.

Russia and Iran, together with China, play central roles in efforts to alter the global order and reduce American influence that grew after the 1990s.

Iran served as a US partner under the shah before the 1979 revolution. Yet the change in government did not push Tehran straight into Soviet arms during the Cold War. Revolutionary leaders preferred a path independent of both Washington and Moscow.

They also faced Soviet forces in Afghanistan and an Islamic uprising against Russian troops. The Iran-Iraq conflict erupted in the 1980s, with Moscow supplying arms to Baghdad.

Iran starts building its missile capabilities

In the 1990s the situation shifted.

The Soviet Union dissolved and Russian troops withdrew from Afghanistan. American dominance and the so-called New World Order took hold. Both Russia and Iran found themselves in weaker positions within this framework.

From around 1992, shortly after the Gulf War, Moscow began aiding Iran's missile and nuclear efforts over many years. Russian teams finished the Bushehr nuclear plant and maintained nuclear ties through state firm Rosatom.

This support mattered because the United States had displayed its advanced military reach through precision strikes that overwhelmed Iraqi forces. Iran and Russia chose to wait for better conditions.

Changes continued. In 1996 China launched the SCO with several Central Asian states and Russia. The BRICS economic group also formed in the late 1990s and early 2000s. These groups gave Iran chances to cooperate with non-Western partners and gain Russian technology.

Iran advanced its missile work with help from North Korea, China, and other sources. Russian firms faced accusations of passing missile technology to Tehran. The partnership let Russia help Iran keep key strategic assets while Iran offered Moscow a way to offset US power over the long term.

Russian leader Vladimir Putin accepted a patient approach, much like China's strategy of building strength quietly before acting. Chinese policy under Deng Xiaoping stressed avoiding clashes while growing economic and national power after the Mao years. Later leaders largely followed this line through the 1990s and into the 2000s even as China's economy expanded.

Under Xi Jinping since 2012, China has moved away from restraint. Its military grows stronger and it uses a more direct diplomatic style that challenges criticism openly.

Putin viewed the 1990s as a period of Russian humiliation, especially during the Kosovo conflict. He restored power step by step by defeating Chechen rebels and then engaging Georgia in 2008.

In 2014 Russia seized Crimea and parts of eastern Ukraine's Donbas region.

In 2015 Moscow entered the Syrian conflict. Russia and Iran coordinated there. Iran's Qasem Soleimani helped encourage Putin's decision to intervene.

For years the two countries led talks in Astana with Turkey and hosted by Kazakhstan.

After the Ukraine invasion, meant to speed Western decline, events did not unfold as Moscow hoped. Iran supplied Shahed drones that Russia used in large numbers against Ukrainian targets, yet these attacks have not brought Russia victory.

Russia-Iran ties played a part in the 2015 nuclear agreement

Overall the Iran-Russia link has not produced major successes for either side.

Still each views helping the other against the US and the West as useful. Moscow backed Iran's 2015 nuclear deal. Russian involvement proved important to the agreement. When Barack Obama took office in 2009 his team sought better relations with Russia and focused on Iran's nuclear program.

One early step was dropping missile-defense plans in Poland and the Czech Republic in favor of a phased system. Officials said the change better matched the Iranian missile threat, and Moscow approved. Obama then sought Russian help in talks with Tehran. Russia joined the P5+1 process that led to the 2015 deal, allowing Moscow to act as both rival and helpful partner to Washington.

This background explains current events. Russia has backed Iran for decades and seeks a multi-polar order. Nations such as Pakistan and Turkey share similar goals. Moscow may see US and Israeli tensions with Iran as a chance to divert attention and resources away from Ukraine.

Iran views the struggle as stretching across Middle East fronts from Jordan to Lebanon, Iraq, and Yemen.

Russia sees it as a wider contest, and China agrees. Moscow aims to turn Iran against the US much as it believes Ukraine was turned against Russia.