European nations worked Monday to keep alive diplomatic efforts to curb the Israel-Iran war as the two countries traded strikes following the United States’ weekend attack on Iran’s nuclear program.

Satellite images analyzed by The New York Times show the extent of damage at the three nuclear facilities hit by the United States. Fordo is Iran’s most critical nuclear enrichment facility, housed deep inside a mountain to shield it from attacks.

The move, the first time the U.S. has attacked Iran, is a major escalation of the conflict between Israel and Iran.