The US military has developed strike plans that could include using the GBU-43/B Massive Ordnance Air Blast Bomb, also known as the "mother of all bombs", against Iranian energy infrastructure and nuclear sites if President Donald Trump orders renewed combat operations, CNN reported on Thursday citing US officials familiar with the matter.
The potential deployment of the largest non-nuclear bomb in the US arsenal would mark a significant development in the war, although officials familiar with military planning discussions told CNN questions remain over its effectiveness in achieving Washington's strategic objectives.
Reuters could not immediately verify the report.
Iran, meanwhile, has placed its military on heightened alert, conducting new missile tests in recent days and threatening to unveil additional weapons.
Tehran has also warned Washington and regional governments that another round of war could trigger retaliation across a wider geographical area, including potential ground incursions.
The US Department of War recently reported that the death toll of US personnel in its war on Iran is 21 killed and 865 wounded in an acknowledgement that losses faced during the conflict were greater than previously admitted.