The attack was the deadliest on Niger’s armed forces in years, and took place in a remote area where jihadists linked to the Islamic State have been active.
The one-day nationwide strike by the National Union of Electricity Employees (NUEE) on Wednesday has been suspended.
Sources said the officer was the only one immediately confirmed killed in the attack.
Modest inventory greeted with scepticism in Zimbabwe, where dictator was thought to have amassed fortune over 40 years.
More than 175 million people are without access to electricity services in the West Africa.
At least 14 people were shot dead in an attack on a church in eastern Burkina Faso on Sunday morning.
The protest in the capital, Abuja, is part of a series of rallies to be held across the country.