Joint Chiefs of Staff Chairman Gen. Joseph Dunford revealed Wednesday that he was the driving force behind the recent U.S. deployments to the Persian Gulf region, which he recommended after reviewing intelligence that indicated an ominous pattern in Iranian actions.

“We saw something that looked more like a campaign than individual threat,” Dunford said at an event at the Brookings Institution. The intelligence covered a wide area and indicated Iran and its proxies were preparing coordinated attacks. “It was the geographic span and the perception that that activity would try to be synchronized in time that caused us to look at that threat differently than 40 years of malign activity by the Iranians.”

“So malign activity and threats to our forces by the Iranians were not new,” Dunford said, “but a more widespread, almost campaignlike perspective for the Iranians was what we were dealing with.”

Dunford said he had been seeing worrisome things in the intelligence reports for weeks, but it all seemed to come together in the last week of April.

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“I began to see more clearly things that I've been picking up on over a period of months,” he said. “I remember very clearly it was the 3rd of May, was on a Friday, and what was qualitatively different about the threat stream we had seen was it was multiple threat streams that were all perhaps coming together in time.”

Acting Defense Secretary Patrick Shanahan, speaking to reporters traveling with him to Jakarta, Indonesia, said Dunford came to him and made the case that what he was seeing was something very different. “This was an anomaly,” Shanahan said. “It was so credible that we moved back quickly. It was a matter of hours.”

Shananan said there were two types of threats. “Iranian activity in the region around their proxies, disruption in the Straits of Hormuz, ballistic missile programs, nuclear programs,” he said, “are the basis for the pressure campaign.” The more immediate threats are to U.S. forces in the region and shipping in the Strait of Hormuz.

“The response we've taken is a threat to the flow of energy and a threat to our men and women and our interests there in the region,” he said of the dual threats. “One with a big 'T' and one with a small 'T,' and the small 'T' is the energy flow and our people in the region. The broader threats are really what the maximum pressure campaign is addressing.”

[Also read: Pentagon publicly rebukes top British general on Iran threat]

“When the president says he doesn't want a war with Iran, I think that's pretty clear, right?” said Shanahan, insisting that the deployments were defensive in nature, designed to increase force protection and send a strong signal of resolve to Iran. “I don't think anyone wants a war with Iran. I don't think you'll find people in the national security [realm] at present who wants a war with Iran. Nobody wants a war.”

Dunford, after consultations with U.S. Central Command chief Gen. Frank McKenzie, wanted reinforcements in four areas: increased surveillance and reconnaissance to monitor Iran’s activities, an engineering battalion to harden facilities, and in the event of an attack, more air power and Patriot missile defenses. “That was the recommendation that the chairman made and I approved it.”

In the end, the moves were modest but sent a big message. The total number of additional troops deployed to Saudi Arabia and Qatar was less than 1,000. “We didn't really discuss a higher number,” said Shanahan. “I would make the argument it deterred attacks on our people in Iraq.”

Still, Shanahan said, “I would just say the threat remains.”

[Previous coverage: Gen. Joseph Dunford: On the frontlines, but playing it down the middle]