Israel is trying to produce solid evidence for its assertion that Hamas has been using tunnels under Al-Shifa Hospital in Gaza as a command center. But an Israeli military-led tour of the hospital grounds with journalists Thursday night showed directly only a shaft in the ground with a staircase, which did not settle the issue.

A definitive answer is almost certain not to come overnight, military experts said.

What is the evidence so far?

Both Israel and the Biden administration say they have evidence that Hamas and Palestinian Islamic Jihad are operating command centers and ammunition depots under hospitals in Gaza, as part of an effort to turn civilians using the hospitals into human shields.

Thursday night’s Israeli military tour showed that the shaft had electrical wiring, along with a metal staircase. In the darkness, it was unclear where the shaft led or how deep it went. The military said it had sent a drone down at least several meters into the shaft, which it said was found in the sand on the northern perimeter of the hospital complex.

Israel has also released a pair of videos from inside Gaza’s main children’s hospital that Israel said showed weapons and explosives found in the medical center, and a room where the military said hostages were kept. The videos contain a series of assertions that could not be independently verified.