US President Donald Trump is reportedly 'increasingly open' to a multi-strike operation on Iran's heavily fortified Fordo nuclear facility.

Fordo is Iran’s second nuclear enrichment facility after Natanz, its main facility, which already has been targeted by Israeli airstrikes. The IAEA said Tuesday it believes the strikes have had “direct impacts” on the facility’s underground centrifuge halls.

Iran has two known underground nuclear enrichment sites, the one Israel attacked on the first day of its assault at Natanz, and another at Fordo. Both sit south of Tehran in central Iran, but Fordo has long been the Iranian nuclear facility of most concern to international monitors and experts.