As the leaders of the protesters opposite the big US embassy in Seoul consider “contributions” to the waterway’s security, they wave signs that read “Do not join a war of aggression.

U.S. President Donald Trump has compelled his ally South Korea to assist in the Middle East battle as Iran has seized control of the strait that’s crucial to global oil supplies.

Around 60 protesters, according to an estimate by AFP news agency, chanted “We cannot send our young people into a sea of death!” on the steps outside Seoul’s Sejong Centre for the Performing Arts.

The protest came a day after South Korean defence authorities announced they have dispatched a fact-finding mission to evaluate the situation in Hormuz, and affirmed they have yet to make a decision regarding deployment.

South Korea is mulling over “contributions” to the U.S. security operations in the strait as long as its military readiness would not be hampered, it said Thursday.

Iran has threatened that if South Korea deployed the unit, any action would have “serious consequences” and would be “considered direct support to the party that committed that aggression”.

“Tehran’s concern is valid,” said Jung Kyung-jik of the civic group People’s Solidarity for Participatory Democracy in an AFP interview.

It would be a direct involvement in an illegal war, he said, referring to Iran’s repeated assertion.

The attacks on Iran include many violations of international law, such as bombing an elementary school and energy infrastructure, he said.

The United States and Israel have been at an impasse for six months in the war they initiated against Iran, which Trump has been unable to get allies to assist him in.

Iran maintains a stranglehold on the strategic strait – which was the conduit for one-fifth of the world’s oil supply before the war -, and Washington has pressed its counter-blockade of Iranian ports.

Choi Young-ok, a member of Korean Peace Solidarity for Sovereignty and Reunification, said that a deployment would “inevitably lead to casualties”.

Such a mission is unacceptable, “sending our troops to an illegal war waged by the United States,” she said.

There’s no need to deploy troops when no other country has done so or said it would.

To use armed forces in the Strait, the government would have to get approval from the National Assembly, which must be voted on by a majority.