The U.S. Navy has doubled to eight the number of counter-mine ships in the Persian Gulf region, according to the service.
The ships arrived in the region on June 23 for a seven-month deployment, according to a statement from the U.S. 5th Fleet headquarters in Bahrain.
Chief of Naval Operations Admiral Jonathan Greenert disclosed the plan in March at a congressional hearing. The added vessels are the USS Sentry, Devastator, Pioneer and Warrior.
Some Iranian officials had threatened earlier this year to close the Strait of Hormuz, transit point for one-fifth of the oil traded worldwide, in response to international sanctions over its nuclear program. The threats have subsided since then.
Greenert said today that encounters with units of the regular Iranian Navy and with the Iranian Revolutionary Guard Corps in charge of Strait of Hormuz security have been calm “in the last couple of months.”
“Things have been, relatively speaking, quiet,” Greenert told reporters in a briefing at the Pentagon. Iranian naval conduct has been “professional and courteous, committing to the rules of the road,” he said.
Mines in the Strait could prompt insurance companies to raise rates on tankers utilizing the waterway, which in turn could lead at least temporarily to higher oil prices.
U.S. officials who follow Iran for the U.S. Central Command estimated in 2008 that Iran possessed as many as 5,000 mines. That compares with 1,000 mines in the 1980s during its conflict with Iraq and the “tanker war” with the West, when it attempted to block vessels.
Greenert also outlined today Navy plans for a gradual increase in forces to the Pacific as part of the “re-balance” toward Asia and also for the Gulf region.
The U.S. has 25 vessels in the Gulf region today. That number will grow to 34 by 2017 and stay at that level through 2020, according to the Navy.