Concerns about living conditions on a US aircraft carrier that has been deployed in the Middle East for more than 250 days are leading a US senator to demand answers from the military about the vessel and putting more pressure on the Trump administration over the Iran war.

Reports suggest US military members aboard the USS Abraham Lincoln are living with food shortages and broken plumbing and that there have been suicide attempts.

Defence Secretary Pete Hegseth on Thursday called the reports "completely misrepresented".

The carrier left San Diego in November for the South China Sea and was then sent to the Middle East ahead of the attacks on Iran in February. No return date has been announced.

Connecticut Senator Richard Blumenthal listed the reported hardships on the carrier, where about 5,000 people are on board, in a letter to Hegseth: "Shortages of basic supplies, water contamination, plumbing issues, deteriorating mental health, deck safety concerns, and disruptions in the mail system, which have caused many care packages in route to the ship to be lost in transit for months."

"These reports warrant immediate attention," the Democrat, who serves on the Armed Services Committee, wrote, "but they also raise a broader question: whether the Navy can sustain the operational tempo now being demanded of its carrier force."

The Military Times and Stars and Stripes reported on Tuesday that multiple sailors on the carrier had considered suicide or attempted to jump overboard, according to their family members.

CBS News, the BBC's US partner, has reported that last month a sailor went overboard and was recovered safely, citing two unnamed officials. The circumstances are currently under investigation.

Following those reports, a Navy official told the BBC they had not identified an increase in reported suicidal ideation or suicide attempts aboard the ship and that "traditional supply hubs" had been "disrupted by combat actions".

The Navy was putting a priority on "mission-critical supplies".

"First food, then hygiene items, then mail," the official said on Wednesday. "Current reports from the ship confirm continuous access to clean water, functional AC (air conditioning), and healthy meal options."

The deployment was originally set to end in May, but has been repeatedly extended.

Hegseth, while speaking to reporters in Panama on Thursday, said the government makes sure "every ship, every crew, every captain has everything we can provide them at every single moment".

"Some deployments are longer than others, and I have more respect and gratitude for those sailors than anybody," he said. "What they do in those high seas in those austere conditions with less port calls - it's incredible."

On Thursday, the Wall Street Journal and CNN reported that the US is preparing to replace the Lincoln with the aircraft carrier USS George Washington as part of a previously scheduled rotation plan. The BBC has contacted the Pentagon about the reports.