Nigerian President Muhammadu Buhari has said that the Russia-Ukraine conflict and the Sahel insurgency have caused a proliferation of arms in the Lake Chad Basin countries.
He said weapons being used in Ukraine and Russia were "beginning to filter to the region" and arms used in the Libya war "continues to find [their] way" there.
He said this was a major threat to the security of the regional countries of Cameroon, Chad, Niger and Nigeria,
"Regrettably, the situation in the Sahel and the raging war in Ukraine serve as major sources of weapons and fighters that bolster the ranks of the terrorists in the region," he said at the summit for the Lake Chad region in the Nigerian capital, Abuja.
Mr Buhari said the countries in the region must improve border security to stop arms trafficking, noting that the region faced a complex and dynamic security situation.
He said this was "increasingly influenced by the impact of climate change and other variables, including sadly, some external factors".
The summit - attended by presidents of Benin, Chad, Niger, Central African Republic, and representatives of the Cameroon and Libya - approved further joint army operations against Boko Haram and Islamic State group militants active in the region.