BEIRUT (AP) — There are conflicting reports about what caused a Syrian military plane to crash today in a Syrian city that is the de-facto capital of the Islamic State group. Activists say the crash killed eight people.

According to the Britain-based Observatory for Human Rights, the plane was hit by anti-aircraft fire. But an activist based in the city says it may have experienced a technical failure.

A militant website carried pictures of the purported wreckage of what it said was a Syrian warplane shot down by the Islamic State group.

Meanwhile, thousands of residents of the city have fled to nearby villages in anticipation of U.S. airstrikes against the militants.

Activists also report attacks on government troops in Damascus, by rebels who emerged from underground sewers for the dawn attacks. It’s one of the few successful infiltrations of the capital since the Syrian conflict erupted three years ago.

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