Eight US Navy personnel assigned to the USS Abraham Lincoln aircraft carrier attempted suicide during a period that included when the ships undertook combat operations in the war against Iran and the carrier set a modern record for its time at sea, according to a letter from the service’s acting secretary, which was obtained by CNN.

Acting Navy Secretary Hung Cao revealed the number, which has not been previously reported and covers crew members from several ships that travel together, including the carrier, in written responses to questions posed by Sen. Kirsten Gillibrand about the morale and mental health of the USS Abraham Lincoln’s crew. Cao wrote that no service members had killed themselves during the deployment.

“Since the beginning of Lincoln’s deployment, there have been a total of eight suicide attempts across the strike group,” Cao wrote to Gillibrand, a Democrat and member of the Senate Armed Services, in a letter dated Tuesday. “This number includes the Lincoln crew and sailors from the carrier airwing, strike group and destroyer squadron staff, escorting destroyers and all embarked aviation squadrons.”

Between 6,000 and 7,000 US Navy sailors were deployed as part of the Lincoln strike group across roughly a half dozen ships — with the carrier kept out of port for over six months while conducting a high rate of combat operations against Iran.

“Eight attempted suicides is incredibly high,” one US military official told CNN, noting recent carrier strike group deployments have had one or two per year. “The strain of combat ops is much higher than normal deployments. No port calls, constant alerts, etc.”

The Navy did not respond ahead of publication to a request for comment about the letter.

“What Trump and Secretary Hegseth dismissed as ‘fake news’ turned out to be serious and deteriorating conditions for our service members,” Gillibrand said in a statement Wednesday to CNN. “Our troops and their families make immense sacrifices every single day, yet the president dismissed them with open disrespect. That this administration can find endless taxpayer dollars for bombs, ballrooms, and billionaires, but cannot take care of our service members, is completely unacceptable.”

CNN previously reported that two sailors assigned to the Lincoln strike group, one from the carrier and one from another ship, had jumped overboard in recent months. Both were rescued, US officials said. Others were prevented from jumping, according to reports from the Navy Times and Stars and Stripes.

In his letter to Gillibrand, Cao also confirmed that a sailor assigned to the airwing went overboard from the ship in early August but was “quickly recovered” and treated by the Lincoln’s medical department. “Additionally, one sailor attempted to go overboard in March and was stopped by his shipmates. That sailor was also provided immediate medical care and subsequently returned to homeport.”

The Navy previously said in a statement to CNN, “We have not observed an increase in suicidal ideations or attempts aboard the ship. We take every service member’s well-being seriously and have religious, medical and mental health professionals available to assess and address concerns as they arise.”

A US official also previously told CNN that the Navy does not believe there is a correlation between deployment length and thoughts of self-harm, and that man overboard incidents are not unique to this group.