Israel is targeting Iran's nuclear sites. Here's what we know about the radiation risks

Tensions are sky-high as the war between Israel and Iran enters its second week.

Israel is intensifying its strikes on Iran's nuclear program. The United States has warned it might join the effort. And even as experts say the radiation risks are low, the International Atomic Energy Agency (IAEA) has called the situation "deeply concerning" and said it "could result in radioactive releases with great consequences."

Geopolitically, it's already a crisis situation, retired U.S. air force general Philip Breedlove, a former NATO Supreme Allied Commander Europe, told CBC News Network on Friday.

"This needs to be managed to an end whereby Iran is not going to have a nuclear weapon," he said.

For a diplomatic outcome, Iran would need to agree to "persistent, pervasive, intrusive inspections" to ensure it's not building a nuclear weapon — and this is extremely unlikely to happen, Breedlove said. "So this is going to proceed to some sort of conclusion — by force, probably."

But in terms of radiation risks, how concerned should the world actually be about potential nuclear fallout? It depends on the target, experts say. And while so far there's been no evidence radioactive material has been released, the IAEA has warned that could change.

Speaking to the United Nations Security Council on Friday, the head of the IAEA once again called for "maximum restraint" in the conflict to avoid further escalation.

"Armed attack for nuclear facilities should never take place and could result in radioactive releases with great consequences within and beyond boundaries of the state which has been attacked," said Rafael Grossi, its director general.

The attacks so far have caused a "sharp degradation to nuclear safety and security in Iran," he said. "Though they have not so far led to a radiological release affecting the public, there is a danger this could occur."

Israel has announced attacks on nuclear sites in the cities of Natanz, Isfahan, Arak and Tehran, Iran's capital.

The IAEA has reported damage to the uranium enrichment plant at Natanz, to the nuclear complex at Isfahan, including the Uranium Conversion Facility, and to centrifuge production facilities in Karaj and Tehran.

Israel has also attacked Arak, known as Khondab. The IAEA said Israeli military strikes hit the Khondab Heavy Water Research Reactor, which was under construction and had not begun operating, and damaged the nearby plant that makes heavy water. The agency said that it was not operational and contained no nuclear material, so there were no radiological effects.

While the recent strikes at nuclear facilities in Iran have understandably raised concerns, there's no evidence of any release of radioactive material into the environment, Peter Bryant, an associate professor in nuclear safety and radiation protection at the University of Surrey in England, said in an online statement on Wednesday.

"It is important to understand that radiation is easy to detect, even at very low levels, using well-established and highly sensitive monitoring equipment. No unusual levels have been reported," Bryant said.