Two Italian priests and a Canadian nun seized in April by gunmen in northern Cameroon have been released and have arrived in the capital Yaoundé, flanked by heavily armed security forces.

Looking tired, but smiling, the clerics were greeted by the ambassadors of Italy and Canada, local church authorities and an envoy sent by Pope Francis, according to state television.

The Cameroonian presidency thanked those who had worked for their release.

At the time of their abduction, the victims were identified by the Catholic Church as priests Giampaolo Marta and Gianantonio Allegri – missionaries from the diocese of Vicenza in Italy – and the nun as Gilberte Bussières.

The three were taken at gunpoint from their accommodation in the district of Maroua in the early hours of April 5.

While no group has claimed responsibility for the kidnap, suspicion has fallen on Nigerian militant faction Boko Haram, which is active in Cameroon.

In 2013, its members seized and later released a priest and a French family of seven in Cameroon.

Shortly after the clerics’ arrival in the capital, state radio announced the killing by Cameroon security forces of some 40 Boko Haram militants in clashes in the north. A source linked to the president confirmed the clashes, which took place west of the town of Kousseri, in the region bordering Nigeria and Chad.

Cameroon deployed around 1,000 troops to the far north at the end of May 2014, after being criticised by Nigeria for not doing enough to fight the Islamist militants.

Boko Haram fighters have killed thousands of people in an attempt to carve out an Islamic state in Nigeria.