24 February 2015
Last updated at 17:06
The bomber in Potiskum detonated his explosives as people were boarding the bus
Suicide bombings at bus stations in two major commercial centres in northern Nigeria have killed at least 23 people, police and hospital sources say.
A bomber first struck in Potiskum, and hours later a second attack took place in Kano, the main northern city.
Hospital sources said 13 people were killed in Potiskum while police put the number of dead in Kano at 10.
Militant Islamist group Boko Haram has stepped up suicide bombings in northern Nigeria in recent months.
However, it has not yet commented on the attacks.
A witness to the Potiskum blast told the BBC Hausa service that the male bomber tried to board a bus as transport officials were loading it.
The bus was completely destroyed and other vehicles at the Dan-Borno bus station were also affected in the explosion, he said.
More than 30 people were wounded, according to hospital sources.
In Kano, two male suicide bombers alighted from a vehicle at the Kano Line bus station, before detonating themselves, police spokesman Magaji Musa Majiya told the BBC.
Kano is about 360km (223 miles) from Potiskum, the main commercial hub in Yobe state.
Boko Haram has repeatedly targeted both places, despite a state of emergency being in force in Yobe.
On Sunday, a young girl with explosives strapped to her killed five people and wounded dozens at a security checkpoint outside a market in Potiskum.
Boko Haram now controls vast swathes of north-east Nigeria and has displaced more than three million people.
The mounting threat of the Islamist insurgency has already led to the postponement of February’s presidential elections, with the vote now due to take place on 28 March.
The delay is designed to give the Nigerian military time to re-establish its presence in the north-east.
However, opponents of President Goodluck Jonathan have claimed that the delay is actually a political tactic.
The group is under increased pressure from the Nigerian troops as well as those of Chad, Niger, and Cameroon.