Iran has reportedly been developing large cruise missiles that could potentially “eliminate many of the obstacles” toward delivering a nuclear bomb.

Citing several US intelligence and security sources and experts, The New York Times reported Thursday that Tehran has moved closer toward achieving weapons-grade enrichment and could soon possess the technology required to deliver nuclear bombs.

While both American and Israeli intelligence officials have suggested that Tehran would require at least two years to reach sufficient levels of enrichment and build a bomb that could fit atop a missile, the report said “growing gaps in knowledge” about the pace of Iran’s nuclear development could significantly change that estimation.

The report noted that Iran has recently notified inspectors from the International Atomic Energy Agency (IAEA) that it plans to advance its nuclear enrichment efforts at its underground Fordo site, which was previously sabotaged by Israel and the US.

The enrichment to 60% purity — a technical step from weapons-grade levels of 90% — was being carried out using the advanced IR-6 centrifuges at the facility and was described as a response to the IAEA’s resolution last week criticizing Tehran’s lack of cooperation with the nuclear watchdog.

The Times suggested that the Fordo site — located deep within a mountain range — would be “hard to bomb,” even if Israel’s incoming hawkish government led by Benjamin Netanyahu wants to carry out an attack. Netanyahu had reportedly considered ordering a strike on the site when he was premier in 2012. As hopes of returning to the 2015 nuclear agreement with Iran have dissipated, the US has shifted its focus to undermine Iran’s nuclear plans, and according to The New York Times, the Fordo site has been a cause for concern among Pentagon officials.