At least 30 US military personnel suffered minor injuries in recent drone attacks, officials say

At least 30 US military personnel sustained minor injuries from drone and rocket attacks on coalition military bases in Iraq and Syria on October 18, defense officials told CNN on Wednesday.

One of the officials said that four personnel sustained minor injuries from an attack on al-Asad airbase in Iraq on October 18, and an additional 20 personnel suffered minor injuries from an attack that same day on the US garrison in al-Tanf, Syria. It is not clear where the other injuries occurred. CNN previously reported that were some minor injuries in the incidents but not how many.

The officials said that all of the personnel have since returned to duty, but that several continue to be monitored for any additional side effects or injuries. The number of injured has risen as more US troops have reported symptoms in the days following the attacks. The officials declined to elaborate on the nature of the injuries, but some injuries like traumatic brain injury can take several days to diagnose.

Pentagon Press Secretary Brig. Gen. Patrick Ryder said on Tuesday that US and coalition forces have been attacked at least 10 separate times in Iraq, and three separate times in Syria since October 17, via a mix of one-way attack drones and rockets. US officials have attributed the attacks to Iranian proxy groups operating in the region and have warned of a potential for significant escalation by these groups in the near term.

NBC News was first to report the number of minor injuries in Syria and Iraq.

Officials told CNN earlier this week that at this point, Iran appears to be encouraging the groups rather than explicitly directing them. One official said Iran is providing guidance to the militia groups that they will not be punished - by not getting resupplied with weaponry, for example - if they continue to attack US or Israeli targets.

The attacks have ramped up amid the US' support for Israel in its war against Hamas and intensified following a hospital blast in Gaza that Palestinian militants and Israel have blamed on each other. US intelligence officials said on Tuesday that the explosion happened when a rocket launched by a Palestinian militant group broke apart in midair and the warhead fell on the hospital.

Iran supports a number of proxy militia groups in countries across the region through the IRGC-Quds Force, and Tehran does not always exert perfect command and control over these groups. How willing those groups are to act independently is a "persistent intelligence gap," noted one source.

But a senior defense official said the US believes that the proxies are being funded, armed, equipped and trained by Iran, and the US therefore holds Tehran responsible for their actions.

Officials across the administration have reiterated in recent days that the US is preparing for a potential escalation, preparing both defense and offensive capabilities should it become necessary to respond.

The US has around 2,500 troops in Iraq and around 900 in Syria as part of the anti-ISIS coalition, and Secretary of Defense Lloyd Austin said in a statement last weekend that he was deploying additional air defense systems to the region in response to the attacks, including a Terminal High Altitude Area Defense missile system and additional Patriot batteries.

Iran warned on Sunday that the situation could escalate. In a conference with his South African counterpart Naledi Pandor in Tehran, Iran's Foreign Minister Hossein Amir-Abdollahian said that the Middle East is like a "powder keg," according to quotes published by state-aligned Tasnim news.

"Any miscalculation in continuing genocide and forced displacement can have serious and bitter consequences, both in the region and for the warmongers," Abdollahian said, referring to the US and Israel.

The Iranian foreign minister also warned the US and Israel that "if crimes against humanity do not stop immediately, there is the possibility at any moment that the region will go out of control."

This story has been updated with additional reporting.