VIENNA (AP) — The top U.N. official monitoring Iran's nuclear program on Thursday rejected Tehran's claim that its military sites were off-limits to inspection, saying his agency needs access to all "relevant locations" if suspicions arise of possible hidden atomic activities.

The comments by International Atomic Energy Agency chief Yukiya Amano are significant — his agency is policing the deal capping atomic activities that Iran says are peaceful but the U.S. suspects are a covert pursuit of nuclear arms.

Adding to their weight is their timing. President Donald Trump has repeatedly criticized...