At least 14 people, including seven children, have been killed when a bus carrying students ran over an improvised explosive device in northern Burkina Faso, according to the government.

It was not immediately clear who was responsible for Saturday's blast, which hit one bus in a convoy of three that was carrying 160 passengers in all, the government said in a statement on Sunday.

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"The provisional toll is 14 dead," the statement said, adding that 19 more people were hurt, three of them seriously.

Seven children and four women were among the dead, the statement said.

The incident occurred in Sourou province, near the border with Mali, where armed groups with links to al-Qaeda and ISIL (ISIS) have increased attacks over the past two years despite international efforts to stamp them out.

The violence, which has ignited ethnic and religious tensions, has killed hundreds of people since the start of 2015 when insecurity began to spread across the Sahel region.

Last month, attackers killed 35 mostly female civilians after raiding a military outpost in Soum Province, also in Burkina Faso's north. About 87 attackers and local security forces were killed in the clash, authorities said.

In a televised address on Tuesday, President Roch Marc Christian Kabore insisted that "victory" against "terrorism" was assured.

Five Sahel states - Burkina Faso, Mali, Mauritania, Niger and Chad - have joined forces to combat the violence in the fragile region that lies between the Sahara and the Atlantic.