The Thursday strike on the B1 bridge in Karaj, west of the capital, Tehran, may come to define the next phase of the US-Israel war with Iran — not because of its immediate military impact but because of what it signals.

For weeks, the conflict had largely followed a familiar pattern: long-range strikes, calibrated escalation and competing claims of battlefield success. But the deliberate targeting of a major infrastructure project — which Iranian state media said was struck twice, with the second hit occurring as emergency teams responded — marks a shift toward a broader, risk-laden strategy.

The message from Washington has been explicit. In the hours surrounding the strike, President Donald Trump doubled down on threats to dismantle Iran's infrastructure, warning that the United States could bomb the country "back to the Stone Ages." In subsequent social media posts, he confirmed the destruction of the bridge and promised "much more to follow," including potential attacks on power plants.

The warning, more than rhetorical escalation, reflects a transition toward degrading Iran's capacity to sustain both its military operations and domestic stability.