DAMASCUS -- An explosion shook the eastern countryside of the southern Syrian province of Daraa on Sunday night, the Syrian Observatory for Human Rights said.

The war monitor reported that the explosion coincided with Jordanian warplanes flying over the Syrian-Jordanian border.

Local news outlets said that Jordanian aircraft conducted three airstrikes near the Nasib border crossing, targeting a suspected mobile unit, possibly a small transport bus, which caught fire as a result.

The Jordanian army said in a statement that its air defense radar system has detected suspicious aerial movements from an unknown source along the border with Syria.

Jordanian airstrikes have previously targeted alleged drug traffickers attempting to smuggle drugs into Jordan from Syria.