After a Iranian weapons depot mysteriously exploded on Saturday, a "Western intelligence source" told Time what many observers already believed to be true — that Israel was behind it.

The explosion came the same week as a U.N. report claiming that Iran had mastered much of the technology necessary to build nuclear weapons and more speculation that Israel was preparing to act to stop those weapons from being finished. Then, suddenly, a major explosion (reportedly felt up to 25 miles away) levels a military base near Tehran, killing 17 people, including General Hassan Moghaddam, a Revolutionary Guard commander who was responsible for Iran's missile development. Coincidence? Most people don't think so.

Officially, Iran says the explosion was an accident that occurred while moving ammunition to a more appropriate site. But in Israel, newspapers are busy chronicling the many "mysterious mishaps" that seem to keep befalling the Iran nuclear program, while not-so subtly hinting that Mossad is the likely culprit. Perhaps it was accident that has merely provided a convenient avenue for Israeli intimidation, but no one has any doubts about their intentions.

Publicly, Israel continues to push back on Iran, saying that the U.N. report is pulling punches and that Iran is even closer to having the bomb than anyone realizes. They may be a little bit farther away after the weekend blast, but no one knows the true extent of the damage or what relation the depot might have had to their nuclear ambitions.

Meanwhile, on Monday Tehran — perhaps in response to an attack, but definitely because of concerns about Israel spies — increased the prison term for Iranian citizens who travel to Israel from three months to five years. Whatever the true story is about the explosion, tensions between the two countries continue to rise and both nations are clearly afraid of what other is capable of.