An army statement described the attack in the northern city of Tripoli as a "terrorist bombing" - a phrase used in the past by the military when it suspects militant Islamist involvement.

It said the bomb had been placed in a bag at a bus stop where soldiers usually gather.

Another 45 people were wounded. Four were in a critical condition, medical sources said.

Red Cross workers ferried casualties to hospital. The ground was spattered with blood and covered in shards of glass.

There were no immediate claims of responsibility for the attack in Lebanon's second-largest city, which has been the scene of fighting between security forces and Islamist militants and sectarian violence linked to political tension in Lebanon.

In Damascus on Wednesday, President Michel Suleiman and Syrian President Bashar al-Assad agreed to establish diplomatic relations between their countries at the ambassadorial level, a move the United States and other Western powers have pressed for.