The rebels also seized two top government officials.[146] On 18 March, the Syrian Air Force attacked rebel positions in Lebanon for the first time, at the Wadi al-Khayl Valley area, near the town of Arsal.[147] On 21 March, a suspected suicide bombing in the Iman Mosque in Mazraa district killed as many as 41 people, including the pro-Assad Sunni cleric, Sheikh Mohammed al-Buti.[148] On 23 March, several rebel groups seized the 38th division air defense base in southern Daraa Governorate near a highway linking Damascus to Jordan.[149] On the next day, rebels captured a 25-kilometre (16-mile) strip of land near the Jordanian border, which included the towns of Muzrib, Abdin, and the al-Rai military checkpoint.[150] On 25 March, rebels launched one of their heaviest bombardments of Central Damascus since the revolt began.