Ghana's President Nana Akufo-Addo said worsening Sahel security was "threatening to engulf the entire West African region".
"Terrorist groups, emboldened by their apparent success in the region, are looking (for) new operational grounds, a development that has triggered a southward drift of the menace," he said.
Under the so-called Accra Initiative, heads of state from the Gulf of Guinea and leaders from Niger and Burkina Faso met in Ghana with representatives from the West African bloc ECOWAS, the EU, Britain and France.
Coastal states Ghana, Benin, Togo and Ivory Coast face increasing threats and attacks from Islamist militants across their northern borders with Burkina Faso and Niger.
The summit in Ghana's capital Accra also comes as more Western nations have withdrawn peacekeepers from Mali after its military junta strengthened cooperation with Russia.
Akufo-Addo called for a "home-grown initiative" to answer the threat as well as a comprehensive approach involving economic and social development to tackle the roots of jihadism.
"We remain firm in our commitment to shoulder a greater part of the responsibility."
The Accra Initiative member countries include Ghana, Togo, Benin, Burkina Faso, Ivory Coast, Mali, and Niger.
At the end of the conference, West African leaders made no major announcements, according to a final communique seen by AFP.
However, they noted "the partners' commitments" to support the initiative, and "recommended that concrete actions, particularly in terms of funding, be taken to support countries severely affected by terrorism."
The Sahel conflict began in northern Mali in 2012, spread to Burkina Faso and Niger in 2015 and now Gulf of Guinea states are suffering sporadic attacks.
Ghana has beefed up security along its northern frontier and has so far escaped any cross-border attacks.
But Benin and Togo in particular have faced threats from across their northern borders with Burkina Faso.
Benin has recorded 20 incursions since 2021 while Togo has suffered at least five attacks, including two deadly assaults, since November 2021.
"For years we have been talking about the risk of contagion of the terrorist threat from the Sahel to the coastal states. Today this is not a risk any more, it is a reality," European Council President Charles Michel told the summit.
British Armed Forces Minister James Heappey aid Accra Initiative countries would likely need different capabilities than the British long-range reconnaissance forces currently in Mali.
"The United Kingdom's armed forces already enjoy great relationships with many of the countries within the Accra Initiative and we stand ready to build on that," he said in Accra.
"But this is a regional problem that you have here in West Africa and it's right that you seek to provide the solution."
France and Germany have announced withdrawal of forces from Mali, citing frictions with the military regime controlling Bamako.
This article has been updated to include all members of the Accra Initiative.