A roadside bomb targeting a bus in Lebanon’s northern port city of Tripoli on Wednesday killed at least 18 people, including nine soldiers. The attack revived concerns about stability after a considerable easing of tensions in the past two months.

The explosion came hours before the start of a two-day visit by Michel Suleiman, Lebanon’s new president and a former army commander, to Damascus for talks with Bashar al-Assad, his Syrian counterpart.