Togo's government on Monday declared a "state of security emergency" in its northern border region to give the armed forces more flexibility to deal with the threat of jihadist attacks.

Eight Togolese were killed in May in a northern town near the border with Burkina Faso, in an attack claimed by Mali-based Al-Qaeda militants.

Jihadist groups in the Sahel nations have been expanding and increasingly threatening the coastal West African states of Ivory Coast, Ghana, Benin, and Togo.

After a Monday ministerial meeting, the government said a state of security emergency had been declared in the Savannah region which covers the country's most northern provinces.

"It will enhance the speed of decision-making and facilitate greater agility for public services and defence and security forces," the statement said.

Government spokesman Akodah Ayewouadan told reporters the measure would last three months and could be extended by the national assembly.

The Mali-based Jama'at Nasr al-Islam wal Muslimin (JNIM) group had claimed responsibility for the attack in May. 

Officials had said at the time that eight Togolese soldiers were killed and 13 others wounded.

A senior security source in Togo told AFP the soldiers were attacked by a group of 60 gunmen who arrived on motorbikes. 

Togolese troops foiled an attack in November last year in the northern village of Sanloaga, making the May attack the first to cause casualties.

West African neighbouring state Benin in May said it was "at war" with terrorism after suffering around 20 attacks, according to the first official tally of these assaults.

It said around 10 of its soldiers had been killed so far.

Benin's first known fatal attack was last December, in which two soldiers were killed near the troubled frontier with Burkina Faso. 

The government responded by announcing increased military deployment in the north to protect the border.

Armed incursions by jihadists linked to Al-Qaeda and the Islamic State (IS) organisation from troubled Sahel nations have also threatened Ghana and Ivory Coast, strengthening fears of a southward push towards the Gulf of Guinea.