Pakistan, July 21 -- U.S. petroleum reserves have fallen to their lowest level in more than four decades amid heightened tensions with Iran. The decline has raised concerns over U.S. energy security and future supply resilience.

According to a Bank of America chart, the United States has about 43 days of oil supply remaining. The figure marks the lowest level recorded since July 1983.

Read more: US taps massive oil reserves after Iran crisis

The latest data from the U.S. Energy Information Administration showed commercial crude oil inventories stood at approximately 409.7 million barrels on July 10. The total was nearly six percent below the five-year average.

Meanwhile, the Strategic Petroleum Reserve declined to 316.5 million barrel...