It looks like Nigerian President Muhammadu Buhari is in the mood to spar with former President Olusegun Obasanjo, an ally turned critic.
Mr Buhari has often ignored Mr Obasanjo's recent criticism of his leadership.
Earlier this year, he said that Mr Buhari should not seek a second term as he had failed in his handling of the economy.
But at an event in the capital, Abuja, Mr Buhari has questioned the impact of $16bn (£11bn) spent on a power project launched during Mr Obasanjo's time in office, Nigerian newspapers are reporting.
He said that “a former Nigerian leader” - without mentioning Mr Obasanjo's by name - was bragging about the amount spent on power sector, yet there was nothing to show for the expenditure.
“Where is the power? Where is the power?," Mr Buhari asked.