The United States will cut the aircraft carriers deployed in the Gulf from two to one due to budget constraints, U.S. media reports said Wednesday, as the Pentagon rails against the possible automatic cuts to defense spending.

According to a report by the National Public Radio, Defense Secretary Leon Panetta has approved a plan to keep just one carrier in the Persian Gulf region, and initial plans to deploy USS Harry Truman to the Gulf later this week have been canceled. The decision has not been formally announced.

The U.S. military has kept two carriers in the Gulf since 2010, when tensions with Iran began to grow. The change in the deployment represents a major shift in U.S. defense capabilities in the region.

Reports said the Pentagon blames the change to budget constraints, as the department faces possible automatic cuts called sequestration in March.

Sequestration, included in the 2011 Budget Control Act, would have automatically cut 500 billion dollars from defense spending over 10 years on top of the 487 billion in spending reductions already identified over the same timeframe. As part of the "fiscal cliff" deal, Congress delayed the cuts for two months from its initial kick-in date at the start of this year.

In a speech to students of the Georgetown University earlier in the day, Defense Secretary Leon Panetta railed against the prospects of sequestration, saying the massive cuts would pose the "most serious readiness crisis" to the country in over a decade.