An additional 1,500 U.S. troops and increased defensive capabilities capabilities are being sent to the Middle East to continue to help deter Iran, the Pentagon announced on Friday.

While departing the White House for a trip to Japan, President Donald Trump described the number of troops headed to the Middle East as a "relatively small number."

"We want to have protection," he told reporters. "We'll be sending a relatively small number of troops -- mostly protective. Some very talented people are going to the Middle East, right now. We'll see what happens."

“I don't think Iran wants to fight," he said."And I certainly don't think they want to fight with us. They cannot have nuclear weapons and under the Obama horrible agreement, they would have had nuclear weapons within five or six years. They can't have nuclear weapons. They understand that,"

The number of troops the president approved on Thursday is much smaller than the 5,000 to 10,000 that had initially been proposed by U.S. Central Command (CENTCOM) as part of the ongoing effort to deter Iranfrom attacking U.S. forces in the Middle East and to boost the force protection of forces already in the region. .

At a briefing, senior Pentagon officials said the 1,500 forces included a Patriot anti-missile battalion of 600 soldiers whose deployment to the region will be extended, engineers who will "harden" existing U.S. military facilities, more manned and unmanned reconnaissance aircraft and a squadron of 12 fighter aircraft.

The lower troop figure was the result of "back and forth" conversations between CENTCOM and the Joint Staff that acting Defense Secretary Patrick Shanahan had described for reporters on Thursday. Those conversations centered on fine-tuning the capabilities being requested by CENTCOM and units available for deployment..

In announcing the deployment, Pentagon officials said the moves were meant to counter a new Iranian "campaign" to target U.S. forces in the region that originated at the "top levels" of Iran's leadership. For the first time U.S. officials directly blamed Iran's Islamic Revolutionary Guard Corps (IRGC) for last week's sabotage attack on four freighters off the coast of the United Arab Emirates.

"We did attribute it directly to limpet mines, and those limpet mines to the IRGC," Vice Adm. Michael Gilday, the director of the Joint Staff, told reporters Friday. Limpet mines are explosive devices that are attached to a target by magnets.

The admiral said that what made the new Iranian campaign different from previous "episodic" actions was that it was spread “across multiple domains”. That included threats to the vital Bab al Mandeb Strait off of Yemen by Iranian proxies, Iran's public comments about closing the Strait of Hormuz, the placement of cruise missiles on civilian dhows, proxy attacks on Saudi Arabia’s oil infrastructure and last weeks rocket attack on the Green Zone in Baghdad that was carried out by an Iranian proxy group.

Katie Wheelbarger, Acting Assistant Secretary of Defense for International Security Affairs, said that the intelligence that was flowing in about the Iranian campaign was significant for experienced Iran watchers like her.

“For those of us that watch this every day , it was a significant change in what we were seeing,” Wheelbarger said. She added that the U.S. intelligence community is seeking to declassify some of that intelligence so that it can be shown to the American public and overseas partners

https://abcnews.go.com/Politics/lawmakers-criticize-senior-trump-officials-iran-intelligence-briefing/story?id=63179848" target="_blank">at this White House meeting.

There are currently 60,000 to 80,000 U.S. troops serving in the Middle East including 14,000 in Afghanistan, 5,000 in Iraq, 2,000 in Syria, 10,000 in Kuwait, 10,000 in Qatar and thousands more at sea and elsewhere in the region.

U.S. officials said the Iranian threat to U.S. forces continues even as Iran has pulled back some weapons systems. Two U.S. officials said that Iran has removed cruise missiles from two of the civilian dhows that Gilday described as posing a risk to U.S. Navy ships, commercial ships and land targets.

The Pentagon officials stressed that the U.S. does not seek a military conflict with Iran.

We want to be clear that based on our posture and based on the assets that we're flowing to theater, we're narrowly focused defensive posture on our part and not in any way designed to be provocative," said Gilday. .

ABC News’ Trish Turner contributed to this report.