Congress’ left-wing “Squad” demanded an end to a U.S.-led investigation into Spain’s embargo of weapon shipments bound for Israel.

In a letter to Federal Maritime Commission Chair Daniel Maffei, Reps. Rashida Tlaib of Michigan, Cori Bush of Missouri and Summer Lee of Pennsylvania called for an end to the independent agency’s investigation into Spain’s decision to deny port entry for ships carrying weapons en route to Israel.

The lawmakers, who have been some of the loudest critics of President Biden’s handling of the Israel-Hamas war, argued that the weapons would be used in the Israeli government’s “ongoing genocide against the Palestinian people in Gaza.”

“This investigation is a reckless insult to our allies in Spain, which has only sought to enforce in good faith its sovereign national policies and uphold international law, including its treaty obligations to prevent genocide,” they wrote.

“It is bad enough that the United States is violating these same obligations and its own domestic laws by sending these weapons,” they said. “We urge you to immediately suspend this obstruction of justice and withdraw this misguided investigation.”

The commission, which is charged with monitoring and evaluating conditions that may affect shipping and U.S. international trade, opened its investigation into Spain, a NATO ally, earlier this month.

The commission’s investigation stemmed from reports that Spain had denied port of entry to three ships going back to May, including vessels enrolled in the U.S.-run Maritime Security Program, which provides ships protection against restrictive and discriminatory licensing because their services are often used by the U.S. military.

Spain halted its own defense companies from shipping arms to Israel last year, and earlier this year, Foreign Minister Jose Manuel Albares said his country was “not going to contribute to any more arms reaching the Middle East.”

“The Middle East needs peace. That is why … this first denial of authorization will start a policy for any boat carrying arms to Israel that wants to dock at a Spanish port,” he said.

The Federal Maritime Commission argued in a statement at the time its investigation was opened that it was “concerned that this apparent policy of denying entry to certain vessels will create conditions unfavorable to shipping in the foreign trade.”

If the investigation finds that Spain has interfered with foreign trade, the commission could hit the country with up to $2.3 million in fines per voyage.

The lawmakers argued that Spain’s decision to deny the ship “are legitimate actions taken by a sovereign state to ensure that it is in compliance with international human rights and humanitarian law. “

They also contended that the commission has no standing to investigate Spain’s actions because denying the vessels does not “threaten the reliable international ocean transportation supply system that the FMC is tasked with safeguarding.”

“No agency of the United States should be in the business of punishing or sanctioning our allies for enforcing the international law that our government has refused to uphold,” they wrote.

• Alex Miller can be reached at amiller@washingtontimes.com.