Spanish Navy frigate ESPS Méndez Núñez broke away from the U.S. aircraft carrier USS Abraham Lincoln and its carrier strike group (CSG) Tuesday as it entered the Strait of Hormuz amid heightened tension between the U.S. and Iran.

The NATO ally’s withdrawal was first reported by Spanish news outlet El Pais. It revealed the ship and its 215-strong crew is now headed to Mumbai, India.

The country’s defense minister Margarita Robles insisted the decision was “not an expression of distaste” over the destination of the USS Abraham Lincoln and its support ships, insisting instead Spain’s decision was “prudent” and “perfectly admissible” under the terms of a two-year cooperation agreement that placed the frigate with the U.S. fleet for advanced training.

“The United States government has embarked on a mission that wasn’t scheduled when the agreement was signed,” Robles told reporters during an official trip to Brussels.

Arrival and doorstep by #ES #Robles @Defensagob at the #FAC #Defence

“The mission for which the #USSAbrahamLincoln combat group is headed wasn’t foreseen at the time when the agreement for the participation of Spanish frigate Méndez Núñez was signed”https://t.co/lN5FAj3eXJ — EU Council TV News (@EUCouncilTVNews) May 14, 2019

Robles said Spain had never given its blessing for the frigate to go on a mission in the Persian Gulf and that it will return to the U.S. fleet once scheduled operations resume.

The new mission no longer had the objective of celebrating 500 years since the first circumnavigation of the world, as envisaged by a bilateral U.S.-Spanish agreement, she added.

U.S. Navy officials did not offer additional details on how the temporary suspension would affect the operation of the strike group.

“I refer you to the Spanish Ministry of Defense for questions regarding future operations with Méndez Núñez,” read a statement from U.S. 5th Fleet reported by the USNI. “We value the strong mil-to-mil relationship with our Spanish allies.”

On May 5, the United States announced it was deploying the USS Abraham Lincoln CSG and a bomber task force to the Middle East in response to a “credible threat” from Iran.

Last Friday, the Pentagon announced the deployment of the amphibious assault ship the USS Arlington and a Patriot missile battery to the region.

For its part, Iran has acknowledged the increase in U.S. forces in the region, dismissing the USS Abraham Lincoln as a “target” not a “threat.”