Fact check: Are there any documented cases of Iran-supported sleeper cells being uncovered in the US or Europe?

1. Summary of the results

Based on the analyses provided, there is limited documented evidence of Iran-supported sleeper cells being uncovered in the US or Europe, though significant concerns exist about their presence and activities.

Documented cases in Europe:

• The UK has experienced at least 15 disrupted plots linked to Iranian sleeper cells ^[1]
• These disruptions suggest active Iranian networks operating in European territories

US situation:

• US Customs and Border Protection officials state that the threat of sleeper cells in the US has "never been higher" ^[2]
• Thousands of Iranian nationals have been documented entering the US illegally, raising security concerns ^[2]
• Iran has explicitly threatened to "activate terror sleeper cells inside US" if attacked ^[3]
• US officials report that Iran has threatened terror attacks inside the US ^[4]

Current threat assessment:

• Intelligence sources warn that Iran may activate sleeper cells in Western nations to carry out terrorist attacks in retaliation for recent military strikes ^[1]
• The Islamic Revolutionary Guard Corps (IRGC) maintains a network of sleeper cells with potential to target civilians, infrastructure, and high-profile targets ^[5]

2. Missing context/alternative viewpoints

The original question focuses solely on documented cases but misses several critical contextual elements:

Operational methods:

• Iran appears to favor asymmetric terror warfare when weakened militarily, making sleeper cell activation a likely strategic response ^[5]
• The threat has escalated significantly following recent US strikes on Iranian nuclear facilities, dubbed "Operation Midnight Hammer" ^[3]

Geographic scope:

• While the question asks about US and Europe, the threat appears more documented in the UK specifically, with 15 disrupted plots providing concrete evidence ^[1]
• The US situation involves more preventive warnings rather than documented uncovered cells

Timing considerations:

• The threat level has intensified dramatically in recent days, with sources from June 20-23, 2025, indicating an immediate and escalating danger ^{[1] [5]}

3. Potential misinformation/bias in the original statement

The original question appears factually neutral and does not contain obvious misinformation. However, it may inadvertently:

Underestimate current threat level:

• By asking about "documented cases," the question might suggest these are historical concerns rather than active, immediate threats as indicated by the most recent intelligence assessments ^{[2] [1]}

Scope limitations:

• The focus on "uncovered" cells may miss the broader picture of active prevention efforts and ongoing threats that haven't yet materialized into attacks ^[1]

Missing urgency:

• The phrasing doesn't reflect that according to current intelligence, the threat is at its highest level ever and may be imminent rather than theoretical ^[2]

The question itself appears to seek factual information without apparent bias, though the timing suggests it may be motivated by recent escalations in US-Iran tensions and military actions.