Washington, Aug 2 (IANS): Iran's Islamic Revolutionary Guard (IRGC) is expected to soon begin a major naval exercise in the Persian Gulf that could demonstrate its ability to shut down the Strait of Hormuz, a crucial conduit for global energy supplies, US officials have said.

According to the officials, the exercise could begin as soon as the next two days.

"We are aware of the increase in Iranian naval operations within the Arabian Gulf, Strait of Hormuz and Gulf of Oman. We are monitoring it closely and will continue to work with our partners to ensure freedom of navigation and free flow of commerce in international waterways," Captain William Urban, chief spokesman for US Central Command, told CNN on Wednesday.

The Strait of Hormuz links the Persian Gulf to the Arabian Sea.

The US Energy Information Administration calls it "the world's most important oil transit chokepoint", with 20 per cent of oil traded worldwide moving through the waterway, which is about 30 miles wide at its narrowest point.

As of now, the US assesses that the IRGC has assembled a fleet of more than 100 boats, many of them small, fast-moving vessels. It is expected that Iranian air and ground assets including coastal defensive missile batteries could also be involved, the officials told CNN.

The IRGC exercise comes as the US has only one major warship, the guided-missile destroyer USS The Sullivans, inside the Persian Gulf, several officials say.

Other US warships are nearby, and there are numerous combat aircraft in the region.