Militants in Nigeria today released their last remaining foreign hostages, setting free two American oil-industry workers and one Briton after more than five weeks in captivity.

Nigeria’s president deployed tens of thousands of police and army troops on foot and in armoured cars today, appealing for calm on the eve of countrywide municipal elections already marred by assassinations and other attacks.

Two of seven foreign oil workers kidnapped by ethnic militants in Nigeria’s volatile oil delta have been released, a state government official said today.