The United States' military action against Iran's nuclear facilities over the weekend has sparked a notable increase in security concerns across the nation.

The bombings have led to heightened tensions with Iran, as confirmed by Obama-era Homeland Security chief Jeh Johnson, and subsequent security measures in the U.S., including the arrests of over a dozen Iranian nationals and fears of potential sleeper cells, as Fox News reports.

Following the bombing events, American law enforcement agencies have been on high alert. Within days, over a dozen Iranian nationals, some of whom were in the United States unlawfully, were detained.

These arrests have been linked to ongoing concerns about potential acts of retaliation, notably as the detained individuals include those with prior military backgrounds and accusations of violent crimes.

In a development adding to the gravity of the situation, Iranian state television has reportedly declared that all U.S. citizens and military personnel in the region are now considered lawful targets. This statement underscores the complex geopolitical ramifications of the weekend's bombings, compounding fears at home.

Heightened concerns prompt forceful response

In response to these emerging threats, a memo from the Department of Homeland Security has surfaced, indicating a "heightened threat environment" was circulating internally. The warning connects the bombing incidents directly to the ongoing Israel-Iran conflict and highlights potential domestic repercussions.

Moreover, Immigration and Customs Enforcement (ICE) reported successful operations leading to the apprehension of more than a dozen undocumented Iranian nationals.

These individuals were closely monitored by law enforcement agencies, who had reportedly been keeping track of their movements and interactions for some time prior to their arrests.

Border czar Tom Homan, offering his insight, expressed concerns regarding the unknown variables surrounding these individuals.

"We don't know who they are, where they came from, why they're here, but they got away," he noted, pointing out the challenge faced by enforcement agencies trying to interpret the intentions of such individuals remaining in the United States.

Focus on potential sleeper cells

Johnson has articulated the severity of these developments. He signaled these hidden internal threats as a top-tier concern for domestic law enforcement, particularly when it involves individuals having affiliations with groups such as Hezbollah or the Iranian Revolutionary Guard Corps (IRGC).

Johnson stated, "The presence in this country of undocumented migrants or Iranian nationals who have links to Hezbollah, IRGC, is, in my judgment, a domestic law enforcement concern of the highest magnitude." His comments have pointed to a growing concern regarding sleeper cells that may not always act under direct orders from their foreign sponsors.

Expressing concern, Johnson explained that these sleeper agents might independently decide to take action, increasing the complexity of the threat landscape.

"Somebody who's here in the United States who has links to the IRGC, to Hezbollah, may decide to take matters into their own hands," he suggested.

Resources diverted to bolster defense

In response, the Federal Bureau of Investigation has strategically redirected its resources, placing greater emphasis on counterterrorism and the need for enhanced cybersecurity measures. The move indicates a national pivot towards preemptive defensive strategies in light of the increased risk.

Concerns over independent extremist activities have stressed the importance of public vigilance. Johnson has continued to endorse the longstanding safety program, reminding citizens that "‘If you see something, say something’ is still a valid public safety tool... It does make a difference."

The steps American law enforcement and security agencies take next will likely rest on intelligence emerging from these recent arrests and ongoing surveillances. As tensions continue to simmer, multifaceted preventive measures will be critical to ensuring public safety.

The developments surrounding these events remain fluid. The situation underscores not only the complex international relations at play but also the tangible impact these have on national security and domestic policy.