How South Korea finds itself trapped in the US-Iran war

Tehran has threatened "serious consequences" for South Korea if it interferes in the US-Israel war on Iran.

Key points

• South Korea became one of the US's closest allies after Washington backed Seoul against Pyongyang in the Korean War of 1950.
• The country relies on the Gulf supplies via the Strait of Hormuz for 60 to 70 percent of crude imports, meaning supply is being severely hit.
• In 2025, nevertheless, Washington imposed a 25 percent tariff on the country, testing relations.
• The Ulchi Freedom Shield (UFS) exercises are meant to sharpen Seoul's readiness in case of a North Korean attack.
• South Korean Foreign Minister Cho Hyun remarked in parliament there was no warning from the US.

For context, the warning comes against the backdrop of reports that Seoul is mulling contributing to the US naval blockade of the Strait of Hormuz passage. It has hampered Iran's oil exports.

In an official note posted on X on Monday, Ministry of Foreign Affairs spokesman Esmaeil Baghaei remarked Iran and South Korea had more than 64 years of diplomatic relations based on mutual respect and that Tehran values that friendship.

Nevertheless, if South Korea joins the United States in its military actions against Iran at a time when the country is defending itself from what he called US aggression and "war crimes against women and children", then there will be consequences, he cautioned.

Baghaei threatened that Iran would regard any military presence or participation in operations by another country in the Gulf and the Strait of Hormuz "would inevitably be regarded as direct support for the aggressor and would have serious consequences".

"No sovereign and responsible country should succumb to US pressure and intimidation and become complicit in acts of aggression and horrific crimes against the great Iranian nation, " he continued.

Seoul did not respond directly, but a Ministry of Foreign Affairs statement on Monday remarked it is communicating with the international community over the situation in the passageway.

Here's what we know regarding how South Korea is getting roped in. Why is South Korea involved?

Seoul, a close ally of Washington, has been under pressure from US President Donald Trump.

When Trump disclosed in an interview, and afterwards online, that he had spoken to South Korean President Lee Jae Myung and asked that Seoul provide "a little hand" in the war on Iran, the problems began in mid-August.

According to media reports, the two leaders had spoken over the phone on May 17. Seoul remarked, "No, thanks!", according to Trump's message on social media.

As South Korea now knows, saying no to Trump has repercussions, nevertheless.

On August 16, Trump confirmed that the US would significantly scale back joint military drills it holds annually with South Korea – the evening before they were scheduled to commence.

In practice, the Ulchi Freedom Shield (UFS) exercises are meant to sharpen Seoul's readiness in case of a North Korean attack. They usually last for more than 11 days but were reduced to five.

In a post on his Truth Social site, Trump asserted the drills were "costly" and that they send a "hostile" signal to North Korean leader Kim Jong Un, with whom he is trying to build a relationship. South Korean Foreign Minister Cho Hyun remarked in parliament there was no warning from the US.

Trump additionally questioned why South Korea would refuse his request when thousands of US soldiers are stationed on the Korean Peninsula.

Although South Korea's military disclosed it received a notification much earlier in June, with Washington citing constraints due to the war on Iran, the US additionally cancelled another military exercise scheduled for September. How has South Korea responded?

President Lee, a liberal who pushes for a dialled-down defence posture, has opted to negotiate. His office earlier published statements saying it hopes for "meaningful dialogue" with Trump.

South Korea's Yonhap news agency documented on Monday that Washington has, even so, "ratcheted up pressure" on Seoul.

On Friday, a South Korean presidential official informed Yonhap that Seoul could consider a military contribution to international measures seeking to free up navigation in the passageway as long as it does not affect the country's defence readiness.

South Korea is looking at various options, the official remarked, including feasible cooperation with France, the United Kingdom and other allies on sending noncombat and search-and-rescue forces.

Meanwhile, the South Korean military has additionally kicked off reviewing assets and troops that could be deployed, including maritime patrol aircraft, explosive ordnance disposal teams and unmanned mine detection and clearing systems, he continued.

Such a move would be unpopular. As have some within Lee's ruling Democratic Party, the opposition has spoken out against a feasible deployment. Plenty of South Koreans have additionally protested against the US-Israel war on Iran. What is the history of US-South Korea relations?

In practice, the US backed Seoul's economic and military expansion in the years after. Under a treaty, some 29, 000 US soldiers have been stationed permanently on the Korean Peninsula since the end of the war. Seoul has additionally relied on US defence might to deter nuclear-armed North Korea.

In return, South Korea backed a number of US wars, including the Iraq War, and is designated an significant non-NATO ally.

In 2025, nevertheless, Washington imposed a 25 percent tariff on the country, testing relations. Seoul opted to negotiate rather than retaliate, leading the US to lower tariffs to 15 percent.

Plenty of South Koreans were additionally alarmed after hundreds of South Koreans were arrested in Immigration and Customs Enforcement (ICE) raids on a Hyundai plant in Georgia in September 2025.

Last October, Trump travelled to Seoul in a historic state visit, and earlier this year, President Lee visited the US. Lee is additionally trying to resume dialogue between Washington and Pyongyang.

How is South Korea being affected by the US-Israel war on Iran?

South Korea is facing an economic crisis. The country relies on the Gulf supplies via the Strait of Hormuz for 60 to 70 percent of crude imports, meaning supply is being severely hit. The war has led to soaring inflation, causing the Korean won to fall to a 17-year low.

Seoul therefore has an interest in freeing up the strait. Although some governing party members could oppose it, nevertheless, under Korean law, the administration will require parliament's approval before a military deployment.

Taken together, the developments around how South Korea finds itself trapped in the US point to a situation that is still moving, and the coming days should bring more clarity.